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                                                                   Exhibit 10.30

                              DATED AUGUST 19, 2005

                                     Between

                      CELANESE EUROPE HOLDING GMBH & CO. KG

                                as the Purchaser

                                       and

                              PAULSON & CO. INC AND

                   ARNHOLD AND S. BLEICHROEDER ADVISERS, LLC,

          EACH ON BEHALF OF ITS OWN AND WITH RESPECT TO SHARES OWNED BY

                            THE INVESTMENT FUNDS AND

                         SEPARATE ACCOUNTS MANAGED BY IT

                                 as the Sellers

                                   ----------

                      SHARE PURCHASE AND TRANSFER AGREEMENT

                            AND SETTLEMENT AGREEMENT

                                   ----------

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THIS SHARE  PURCHASE AND  TRANSFER  AGREEMENT  AND  SETTLEMENT  AGREEMENT  (this
"AGREEMENT") is made on August 19, 2005

BETWEEN:

(1)  CELANESE EUROPE HOLDING GMBH & CO. KG, a limited partnership
     (Kommanditgesellschaft) organized under the laws of the Federal Republic of
     Germany with registered office (Sitz) at Kronberg i.T., registered with the
     commercial register of the Local Court (Amtsgericht) Koenigstein, Germany,
     under registration number HRA 2970 (the "PURCHASER")

AND

(2)  PAULSON & CO. INC., a corporation organized under the laws of the State of
     Delaware, with its principal offices at 590 Madison Avenue, New York, NY
     10022, USA ("PAULSON"), acting on its own behalf as well as with respect to
     the Shares (as defined below) owned by the investment funds and separate
     accounts managed by it; and

(3)  ARNHOLD AND S. BLEICHROEDER ADVISERS, LLC, a limited liability company
     established under the laws of the State of Delaware, with its principal
     offices at 1345 Avenue of the Americas, New York, NY 10105, USA ("ASB" and
     together with Paulson, the "SELLERS"), acting on its own behalf as well as
     with respect to the Shares (as defined below) owned by the investment funds
     and separate accounts managed by it.

The Sellers and the Purchaser are also collectively referred to hereinafter as
the "PARTIES" and each individually as a "PARTY".

PREAMBLE:

A.   Pursuant to a voluntary public takeover offer (the "TENDER OFFER") the
     Purchaser acquired in April 2004 approximately 82.6% of the outstanding
     shares in Celanese Aktiengesellschaft, a stock corporation organized under
     the laws of the Federal Republic of Germany, with registered office (Sitz)
     in Kronberg i.T., Germany, registered with the commercial register of the
     Local Court Koenigstein under registration number HRB 5277 (the "COMPANY").

B.   The registered share capital of the Company in the nominal amount of EUR
     140,069,354 is divided into 54,790,369 registered shares with no par value
     (auf den Namen lautende Stuckaktien) (the "SHARES"). The Shares are
     admitted to trading on the official market (Amtlicher Markt) of the
     Frankfurt Stock Exchange. The Shares are traded on the Frankfurt Stock
     Exchange and through the electronic trading system XETRA under the symbol
     "CZZ", under the German Securities Identification Number
     (Wertpapierkennnummer) (WKN) 575 300 and under the International Securities
     Identification Number (ISIN) DE 0005753008. The Shares were delisted from
     the New York Stock Exchange on June 2, 2004.

C.   On June 22, 2004, the Purchaser and the Company entered into a domination
     and profit and loss transfer agreement (Beherrschungs- und
     Gewinnabfuhrungsvertrag) (the "DOMINATION AGREEMENT"). The Domination
     Agreement was submitted to a shareholder vote, and approved, at an
     extraordinary general meeting of the Company held on July 30 and 31, 2004
     (the "EGM"). The Domination Agreement was registered in the commercial
     register of the Local Court of Koenigstein im Taunus on August 2, 2004 and,
     under


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     the terms thereof, became operative on October 1, 2004. In connection with
     the Domination Agreement, the Purchaser has offered, pursuant to a
     mandatory offer required by Section 305(1) of the German Stock Corporation
     Act, the minority shareholders (ausstehende Aktionare) of the Company a
     "fair cash compensation" (angemessene Barabfindung) in exchange for their
     Shares in the amount of EUR 41.92 per Share (the "MANDATORY OFFER"). In
     addition, under the Domination Agreement, pursuant to Section 304(1),
     sentence 1 of the German Stock Corporation Act, any minority shareholder
     who elects not to tender its Shares into the Mandatory Offer and to remain
     a shareholder of the Company is entitled to receive a certain guaranteed
     fixed annual dividend (Ausgleich) per Share in lieu of any future dividend
     payments.

D.   Following the EGM, certain minority shareholders of the Company, whose
     names are set forth in Annex A (the "ORIGINAL PLAINTIFFS") brought forward
     legal actions with the Frankfurt District Court (Landgericht) and requested
     the court to set aside the shareholder resolutions passed at the EGM
     (collectively, the "ORIGINAL ACTIONS"). Several minority shareholders have
     joined the Original Actions via third party interventions in support of the
     Original Plaintiffs. The Purchaser has joined the proceedings via a third
     party intervention in support of the Company. In September 2004, the
     Frankfurt District Court consolidated the Original Actions (file no. 3-05 O
     112/04). One minority shareholder, Metropol Vermoegensverwaltungs- und
     Grundstuecks-GmbH, Cologne, Germany (the "AVOIDANCE PLAINTIFF" and together
     with the Original Plaintiffs, the "PLAINTIFFS"), brought forward an
     additional action (file no. 3-05 O 61/05) with the Frankfurt District Court
     and requested the court to rule that the shareholder resolutions passed at
     the EGM were void (Nichtigkeitsklage) (the "AVOIDANCE PROCEEDINGS"). In
     addition, several minority shareholders (including Paulson and the
     Plaintiffs) have initiated special award proceedings (Spruchverfahren)
     seeking the court's review of the amounts of the fair cash compensation and
     the guaranteed fixed annual dividend offered under the Domination Agreement
     (collectively, the "AWARD PROCEEDINGS"). In March 2005, the Frankfurt
     District Court dismissed the motions of all minority shareholders regarding
     the initiation of the Award Proceedings as inadmissible. The ruling of the
     court is, however, subject to pending appeals (sofortige Beschwerden)
     (collectively, the "APPEALS") including appeals of Paulson and the
     Plaintiffs with the Frankfurt Higher District Court (Oberlandesgericht).

E.   A ratification resolution (Bestatigungsbeschluss) to ratify the
     shareholders' resolutions passed at the EGM was submitted to a shareholder
     vote, and approved, at the annual general meeting of the Company held on
     May 19 and 20, 2005 (the "AGM"). Following the AGM, several minority
     shareholders of the Company (including Paulson and the Plaintiffs) brought
     forward legal actions with the Frankfurt District Court against the
     shareholders' resolutions passed at the AGM as well, and requested that the
     court set aside the ratification resolution (collectively, the "ADDITIONAL
     ACTIONS"). In June 2005, the Frankfurt District Court has suspended the
     proceedings regarding the Original Actions until a judicially final and
     binding decision is rendered with regard to the Additional Actions and
     consolidated the Additional Actions (file no. 3-05 O 71/05).

F.   In addition to the Original Actions, the Avoidance Action, the Award
     Proceedings, the Appeals and the Additional Actions, certain minority
     shareholders have instituted the legal proceedings set forth in Annex B
     against, among others, the Company and the Purchaser in connection with the
     Tender Offer and the Domination Agreement (these proceedings together with
     the Original Actions, the Avoidance Action, the Award Proceedings, the
     Appeals and the Additional Actions, and together with any and all other
     legal proceedings commenced against the Company or the Purchaser or any of
     their affiliates before, on or


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     after the date hereof relating in any way to the subject matter of any of
     the foregoing, the "LEGAL PROCEEDINGS").

G.   As of today, Paulson and the investment funds and separate accounts managed
     by it own in the aggregate 5,758,299 Shares (the "PAULSON SHARES"),
     representing approximately 11.43% of the outstanding shares of the Company;
     and ASB and the investment funds and separate accounts managed by it own in
     the aggregate 160,000 Shares (the "ASB SHARES" and together with the
     Paulson Shares, the "SELLERS' SHARES"), representing approximately 0.32% of
     the outstanding Shares of the Company. The Sellers' Shares are currently
     held in book entry form within the Clearstream Banking AG booking system in
     various securities accounts of the Sellers and of the investment funds and
     separate accounts managed by the Sellers.

IT IS AGREED as follows:

1.   SUBJECT MATTER OF THIS AGREEMENT; CONDITION PRECEDENT

     The subject matter of this Agreement is (i) the sale and transfer of all
     Shares held by the Sellers and the investment funds and separate accounts
     managed by the Sellers to the Purchaser as well as (ii) the settlement of
     all Legal Proceedings, to the extent the Sellers are a party to the Legal
     Proceedings; (iii) the agreement by the Sellers not to make future
     investments in the Company; and (iv) a general release relating to their
     investment in the Company.

2.   SALE AND PURCHASE OF SHARES

2.1  Paulson hereby sells to the Purchaser, and the Purchaser hereby purchases
     from Paulson, the Paulson Shares; and ASB hereby sells to the Purchaser,
     and the Purchaser hereby purchases from ASB, the ASB Shares. For the
     avoidance of doubt, the sale and purchase of the Sellers' Shares pursuant
     to this Agreement shall include all Shares held, directly or indirectly, by
     the Sellers and the investment funds and separate accounts managed by them,
     irrespective of whether the description of the Shares and the Sellers'
     Shares set forth in recitals B and G of the Preamble or elsewhere herein is
     true and complete.

2.2  The sale and purchase of the Sellers' Shares contemplated by this Agreement
     shall be made with all rights attached to the Sellers' Shares (the
     "ANCILLARY RIGHTS"), including, without limitation, the rights to receive
     dividends and all subscription rights (Bezugsrechte). The right to receive
     dividends shall include the right to receive, in part or in total, the
     guaranteed fixed annual dividend for the current fiscal year 2004/2005 as
     well as the right to receive dividends for all previous fiscal years of the
     Company, to the extent that profits of previous fiscal years have not been
     distributed as of the date hereof. The Ancillary Rights shall also include
     any right to participate in an increase of the amount of the fair cash
     compensation and/or the guaranteed fixed annual payment as a result of, or
     in connection with the Award Proceedings or other proceedings or agreements
     irrespective of whether such increase occurs through a court ruling, an
     agreement amongst the parties to the Award Proceedings or otherwise.

3.   PURCHASE PRICE

3.1  The purchase price for the Sellers' Shares amounts to EUR 51.00 per share
     (the "BASE PURCHASE PRICE"). In addition to the Base Purchase Price and as
     consideration for the Sellers' undertakings and the settlement set forth in
     Section 7 below, the Sellers shall be


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     entitled to an additional payment of EUR 2.00 per share (the "ADDITIONAL
     PURCHASE PRICE"). Thus, the aggregate purchase price (i.e., Base Purchase
     Price and Additional Purchase Price) for the 5,758,299 Shares sold by
     Paulson amounts to EUR 305,189,847.00 (the "PAULSON PURCHASE PRICE"); and
     the aggregate purchase price (i.e., Base Purchase Price and Additional
     Purchase Price) for the 160,000 Shares sold by ASB amounts to EUR
     8,480,000.00 (the "ASB PURCHASE PRICE").

3.2  The Purchaser shall pay the Paulson Purchase Price and the ASB Purchase
     Price in accordance with the provisions of Section 4 below to bank accounts
     of the Sellers specified by the Sellers (the "SELLERS' BANK ACCOUNTS").

     A credit made to the Sellers' Bank Accounts shall have the effect of
     discharging the Purchaser in a corresponding amount from its obligation
     (schuldbefreiende Wirkung) to pay the Purchase Price to the respective
     Seller.

4.   TRANSFER OF SHARES

4.1  The Sellers' Shares are hereby assigned and transferred as follows:

     (a)  Paulson, on its own behalf and on behalf of the investment funds and
          separate accounts managed by it, hereby assigns and transfers to the
          Purchaser who accepts such transfer and assignment, the Paulson
          Shares, which transfer and assignment shall include all Ancillary
          Rights attached to the Paulson Shares.

     (b)  ASB, on its own behalf and on behalf of the investment funds and
          separate accounts managed by it, hereby assigns and transfers to the
          Purchaser who accepts such transfer and assignment, the ASB Shares,
          which transfer and assignment shall include all Ancillary Rights
          attached to the ASB Shares.

     The assignment and transfer of the Paulson Shares shall, however, be
     subject to the condition precedent of complete payment of the Paulson
     Purchase Price by the Purchaser to the bank accounts specified by Paulson;
     and the assignment and transfer of the ASB Shares shall, however, be
     subject to the condition precedent of complete payment of the ASB Purchase
     Price by the Purchaser to the bank accounts specified by ASB (each, a
     "CONDITION TO TRANSFER OF TITLE").

4.2  In order to ensure transfer of title in the Sellers' Shares, the Parties
     shall take the following actions concurrently (Zug um Zug) as soon as the
     Sellers have fully complied with their obligations under Section 7.1(a):

     (a)  The Sellers shall procure that (i) the Paulson Shares are transferred
          to the securities deposit of the Purchaser specified by the Purchaser
          (the "PURCHASER'S SECURITIES DEPOSIT") by making a corresponding
          book-entry transfer (Girosammelgutschrift) concurrently (Zug um Zug)
          with the payment by the Purchaser of the Paulson Purchase Price into
          the Paulson bank accounts; and (ii) the ASB Shares are transferred to
          the Purchaser's Securities Deposit by making a corresponding
          book-entry transfer (Girosammelgutschrift) concurrently with the
          payment by the Purchaser of the ASB Purchase Price into the ASB bank
          accounts.

     (b)  The Purchaser shall irrevocably instruct its bank in writing to (i)
          transfer the Paulson Purchase Price from its cash account with its
          bank to the Paulson bank accounts free of any bank charges, by wire
          transfer in immediately available funds in Euro concurrently with the
          transfer of the Paulson shares to the Purchaser's Securities


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          Deposit; and (ii) transfer the ASB Purchase Price from its cash
          account with its bank to the ASB bank accounts free of any bank
          charges, by wire transfer in immediately available funds in Euro
          concurrently with the transfer of the ASB shares to the Purchaser's
          Securities Deposit.

     (c)  The Parties shall take any other action, make any other declaration
          and execute any such document which is required or which the Purchaser
          reasonably requests to be executed in order to transfer title in the
          Sellers' Shares to the Purchaser.

4.3  The Parties agree that, from the execution hereof and until the occurrence
     of the transfer of the Sellers' Shares to the Purchaser's Securities
     Deposit by way of book entry transfer, the Sellers shall hold the Sellers'
     Shares in custody for the Purchaser, free of any charges or costs.

5.   REPRESENTATIONS AND WARRANTIES

5.1  Each Seller hereby represents and warrants severally by way of an
     independent guarantee (selbstandiges Garantieversprechen) pursuant to
     Section 311(1) German Civil Code (Burgerliches Gesetzbuch ), except as
     otherwise is expressly provided for herein, as of the date hereof and, if
     different, as of the date when the transfer of the Shares pursuant to
     Section 4 above becomes effective, as follows:

     (a)  Paulson represents and warrants that it is a corporation duly
          organized, validly existing and in good standing under the laws of the
          State of Delaware. ASB represents and warrants that it is a limited
          liability company duly organized, validly existing and in good
          standing under the laws of the State of Delaware.

     (b)  Each Seller represents and warrants that it has all requisite power
          and authority to execute and deliver this Agreement and to perform its
          obligations hereunder and to consummate the transactions contemplated
          hereby. Each Seller represents and warrants that the execution and
          delivery of this Agreement, the performance of such Seller's
          obligations hereunder and the consummation of the transactions
          contemplated hereby have been duly and validly authorized by all
          necessary corporate and other proceedings on the part of the
          respective Seller. Each Seller represents and warrants that this
          Agreement has been duly executed and delivered by such Seller, and
          assuming the due execution hereof by the Purchaser, this Agreement
          constitutes the legal, valid and binding obligation of such Seller in
          accordance with its terms.

     (c)  Each Seller represents and warrants that it or the investment funds
          and separate accounts managed by it have good and valid title to the
          Sellers' Shares sold and to be transferred by such Seller, free and
          clear of any liens, claims, encumbrances, security interests, options,
          pre-emptive, drag-along or tag-along rights, rights of first refusal
          or first offer, charges or restrictions of any kind (collectively,
          "LIENS"). Each of the Sellers represents and warrants that upon
          book-entry of the transfer of such Seller's Shares in the Purchaser's
          Security Deposit, good and valid title to such Seller's Shares sold
          and to be transferred by such Seller will pass to the Purchaser, free
          and clear of any Liens, except for Liens arising from acts of the
          Purchaser.

5.2  The Purchaser hereby represents and warrants by way of an independent
     guarantee (selbstandiges Garantieversprechen) pursuant to Section 311(1)
     German Civil Code (Burgerliches Gesetzbuch), except as otherwise is
     expressly provided for herein, as of the


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     date hereof and, if different, as of the date when the transfer of the
     Shares pursuant to Section 4 above becomes effective, as follows:

     (a)  The Purchaser represents and warrants that it is a limited partnership
          (Kommanditgesellschaft) organized, validly existing and in good
          standing under the laws of the Federal Republic of Germany.

     (b)  The Purchaser represents and warrants that it has all requisite power
          and authority to execute and deliver this Agreement and to perform its
          obligations hereunder and to consummate the transactions contemplated
          hereby. The Purchaser represents and warrants that the execution and
          delivery of this Agreement, the performance of its obligations
          hereunder and the consummation of the transactions contemplated hereby
          have been duly and validly authorized by all necessary corporate and
          other proceedings on its part. The Purchaser represents and warrants
          that this Agreement has been duly executed and delivered by it, and
          assuming the due execution hereof by the Sellers, this Agreement
          constitutes the legal, valid and binding obligation of the Purchaser
          in accordance with its terms.

6.   REMEDIES

6.1  If it becomes apparent that one or several of the representations and
     warranties given by the Sellers in this Agreement are not accurate or
     incomplete or in case of a breach of any of the other obligations of the
     Sellers under this Agreement, then the Purchaser may at its sole discretion
     request from the Sellers - who shall be liable for their respective
     obligations severally (teilschuldnerisch) - either

     (a)  that the respective Seller put the Purchaser into the position the
          Purchaser would be in had the relevant representations and warranties
          been correct and complete or the relevant obligation not been
          breached, as the case may be; or

     (b)  compensation for the damages (Schadensersatz wegen Nichterfullung)
          incurred by the Purchaser because of the inaccuracy or incompleteness
          of the relevant representations and warranties or the breach of the
          relevant obligation, as the case may be, provided, however, that the
          Purchaser shall only be entitled to be compensated for damages after
          (i) the Purchaser has granted the respective Seller a period of at
          least 10 calendar days in which to bring about the position the
          Purchaser would be in had the relevant representations and warranties
          been correct and complete or the relevant obligation not been
          breached, as the case may be, (each, a "RECTIFICATION") and the
          respective Seller fails to do so within said time period or (ii) if
          Rectification is not possible or sufficient.

6.2  If it becomes apparent that one or several of the representations and
     warranties given by the Purchaser in this Agreement are not accurate or
     incomplete or in case of a breach of any of the other obligations of the
     Purchaser under this Agreement, then the Sellers may at their sole
     discretion request from the Purchaser either

     (a)  that the Purchaser put the Sellers into the position the Sellers would
          be in had the relevant representations and warranties been correct and
          complete or the relevant obligation not been breached, as the case may
          be; or

     (b)  compensation for the damages (Schadensersatz wegen Nichterfullung)
          incurred by the Sellers because of the inaccuracy or incompleteness of
          the relevant representations and warranties or the breach of the
          relevant obligation, as the case


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          may be, provided, however, that the Sellers shall only be entitled to
          be compensated for damages after (i) the Sellers have granted the
          Purchaser a period of at least 10 calendar days in which to bring
          about the position the Sellers would be in had the relevant
          representations and warranties been correct and complete or the
          relevant obligation not been breached, as the case may be, (each, a
          "RECTIFICATION") and the Purchaser fails to do so within said time
          period or (ii) if Rectification is not possible or sufficient.

6.3  Except as otherwise provided for in this Agreement, any claim by the
     Purchaser or the Sellers, as the case may be, based on the incorrectness or
     incompleteness of the representations and warranties shall become
     time-barred (verjahrt) on December 31, 2008. With respect to all other
     claims of the Purchaser against the Sellers or the Sellers against the
     Purchaser, as the case may be, and except as otherwise expressly provided
     for in this Agreement, the statutory limitation periods shall apply. With
     respect to the suspension (Hemmung) and interruption (Neubeginn) of the
     statute of limitations time periods set forth herein, the statutory regime
     applies.

6.4  Except as otherwise provided for in this Agreement and legally permissible,
     any claims of the Purchaser relating to avoidance (Anfechtung), rescission
     (Rucktritt) and the reduction of the Purchase Price (Minderung), as well as
     claims based on breach of pre-contractual duty (culpa in contrahendo,
     Section 311(2) BGB) shall be excluded, except to the extent such claims are
     the result of gross negligence or willful misconduct on the part of the
     Sellers.

7.   SELLERS' UNDERTAKINGS; SETTLEMENT

7.1  With respect to the purchase and acquisition of the Sellers' Shares by the
     Purchaser, the Sellers are prepared to accept the shareholders' resolutions
     passed at the EGM and the AGM and to acknowledge the legal effectiveness of
     the Domination Agreement. Therefore, the Sellers irrevocably undertake
     vis-a-vis the Purchaser and the Company (echter Vertrag zugunsten Dritter)
     to take the following actions without delay and hereby irrevocably makes
     the following declarations, as the case may be:

     (a)  Each of the Sellers shall, and shall procure that its affiliates,
          their respective past and current employees, officers, directors,
          representatives, agents, assigns, successors, predecessors, parents,
          subsidiaries, investors and shareholders, except to the extent such
          investors and shareholders are not acting with respect to an
          investment in such Sellers' investment funds and separate accounts
          (the "RELATED PARTIES"), irrevocably withdraw and abandon all actions,
          applications and appeals (Klage- bzw. Antragsrucknahme; Rucknahme von
          Rechtsmitteln) it brought forward in connection with the Tender Offer
          and the Domination Agreement, including in connection with the Legal
          Proceedings; and the Sellers hereby irrevocably waive the respective
          causes of action (Verzicht auf die geltend gemachten Anspruche).

     (b)  Each Seller on its own behalf and on behalf of its Related Parties
          hereby irrevocably waives any objections it might have against the
          legal effectiveness and validity or the lawfulness of the
          shareholders' resolutions passed at the EGM and the AGM, the
          Domination Agreement and the Tender Offer as well as any action taken
          under or in connection with the Domination Agreement and the Tender
          Offer. Each Seller shall take any action or make any additional
          declaration which the Purchaser or the Company reasonably requests
          from such Seller to maintain the legal effectiveness and registration
          of the Domination Agreement.


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     (c)  Each of the Sellers hereby acknowledges the effectiveness, validity
          and the lawfulness of the shareholders' resolutions passed at the EGM
          and the AGM, the Domination Agreement and the Tender Offer as well as
          any action taken under or in connection with the Domination Agreement
          and the Tender Offer. Each Seller shall, and shall procure that its
          Related Parties, refrain from taking any action (either in court or
          out of court) to challenge directly or indirectly the legal
          effectiveness and validity or the lawfulness of the shareholders'
          resolutions passed at the EGM and the AGM, the Domination Agreement
          and the Tender Offer as well as any action taken under or in
          connection with the Domination Agreement and the Tender Offer; each of
          the Sellers shall, and shall procure that its Related Parties, further
          refrain from initiating any other legal proceedings of whatever nature
          (including award proceedings), in any court or tribunal under the laws
          of any nation, state or territory, based on the alleged
          ineffectiveness, invalidity or unlawfulness of the shareholders'
          resolutions passed at the EGM and the AGM, the Domination Agreement
          and the Tender Offer as well as any action taken under or in
          connection with the Domination Agreement and the Tender Offer. Each of
          the Sellers shall, and shall procure that its Related Parties, also
          refrain from directly or indirectly supporting or encouraging any
          other person to take or to continue any such proceedings. In
          particular, each of the Sellers shall, and shall procure that its
          Related Parties, refrain from taking any action in connection with,
          and shall not directly or indirectly support any (existing or former)
          minority shareholder of the Company or any other person in connection
          with the Legal Proceedings or any other legal proceedings relating to
          the shareholders' resolutions passed at the EGM and the AGM, the
          Domination Agreement and the Tender Offer as well as any action taken
          under or in connection with the Domination Agreement and the Tender
          Offer. Each of the Sellers shall, and shall procure that its Related
          Parties, not make available any work product or other documentation
          prepared by itself, its affiliates or its former and present advisors
          (including legal advisors, accountants and financial advisors) related
          to or otherwise relevant for the Legal Proceedings to any other
          person.

     (d)  Each of the Sellers shall, and shall procure that its Related Parties,
          refrain from acquiring, directly or indirectly, any Shares or any
          other investment in the Company and shall, and shall procure that its
          Related Parties, not hold or otherwise control directly or indirectly
          any Shares or other investment in the Company in the future.

     (e)  Without limiting the generality of the foregoing, each of the Sellers
          shall, and shall procure that its Related Parties, refrain from taking
          any action (either in court or out of court) to challenge directly or
          indirectly any shareholders' resolutions or corporate decisions of the
          Company or to initiate any legal proceedings of whatever nature
          (including award proceedings) , in any court or tribunal under the
          laws of any nation, state or territory, in connection with such
          shareholders' resolutions or corporate decisions including, without
          limitation, in connection with an amendment of the Company's articles
          of association, a delisting of the Company, a squeeze-out or a
          conversion of the Company or any other type of restructuring of the
          Company (each, a "FUTURE TRANSACTION"). The Sellers shall also
          refrain, and shall procure that its Related Parties, from directly or
          indirectly supporting or encouraging any other person to take any
          action (either in court or out of court) to challenge or to continue
          to challenge, as the case may be, the legal effectiveness, validity or
          lawfulness of a Future Transaction or to initiate any legal
          proceedings of whatever nature (including award proceedings), in any
          court or tribunal under the laws of any nation, state or territory, in
          this connection.


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7.2  Upon withdrawal and abandonment by the Sellers of all actions and
     applications in accordance with Section 7.1(a), the Purchaser or the
     Company (as the case may be) shall, with respect to each such action,
     application and appeal, as the case may be, waive the initiation of
     proceedings regarding the determination of legal fees (Verzicht auf die
     Einleitung eines Kostenfestsetzungsverfahrens) with respect to the Sellers.
     The Purchaser and the Company will, however, not reimburse the Sellers for
     any costs, in particular lawyers', accountants' and other consultants'
     fees, incurred by the Sellers through such actions and applications or
     proceedings or the preparation thereof and the Sellers hereby irrevocably
     waive any claims in this respect.

7.3  Upon consummation of the sale and purchase of the Sellers' Shares in
     accordance with Section 4 above, all claims of the Sellers arising from and
     in connection with the Tender Offer and the Domination Agreement or any
     action taken under or in connection with the Domination Agreement and the
     Tender Offer are, except for the Parties' rights and obligations under this
     Agreement, settled (erledigt). In addition, each of the Sellers on behalf
     of itself and its Related Parties hereby irrevocably waives any and all
     actual or potential claims whatsoever (whether or not relating to the
     subject matter of the current Legal Proceedings) arising out of, or
     relating to the transactions or matters referred to directly or indirectly
     in this Agreement that such Seller has, or in the future may have, against
     the Purchaser, the Company or any of the Purchaser's or the Company's past,
     current and future Related Parties under the laws of any nation, state or
     territory. The Purchaser hereby accepts such waiver.

8.   PURCHASER'S UNDERTAKINGS; INCREASE OF FAIR CASH COMPENSATION

8.1  With respect to the sale and transfer of the Sellers' Shares by the Sellers
     and the settlement between the Parties in accordance with Section 7 above,
     the Purchaser undertakes vis-a-vis the Sellers, subject to compliance with
     applicable law, to increase the fair cash compensation (Abfindung) under
     the Mandatory Offer of EUR 41.92 per Share resolved upon during the AGM
     (the "ORIGINAL CASH COMPENSATION") by an amount of EUR 9.08 per Share (the
     "ADDITIONAL CASH COMPENSATION") up to an aggregate amount of EUR 51.00 per
     Share for all minority shareholders that accept the Mandatory Offer on or
     prior to September 29, 2005, provided, however, that a minority shareholder
     shall only be entitled to the Additional Cash Compensation if such
     shareholder irrevocably declares by signing a waiver declaration the form
     of which is attached as Annex C that such shareholder (i) has not filed or
     has withdrawn (as the case may be), and will not file, an application for
     the initiation of award proceedings, and irrevocably waives any and all
     rights to initiate and carry out award proceedings in connection with the
     Domination Agreement; (ii) has not adhered, and will not adhere, to
     applications and has not, or will not, facilitate award proceedings in
     connection with the Domination Agreement in any other way, whether directly
     or indirectly; and (iii) irrevocably waives any and all rights to
     participate in an increase of the amount of the fair cash compensation
     and/or the guaranteed fixed annual payment as a result of, or in connection
     with the Award Proceedings or other proceedings or agreements irrespective
     of whether such increase occurs through a court ruling, an agreement
     amongst the parties or otherwise. Minority shareholders who accept the
     Mandatory Offer after September 29, 2005 shall not be entitled to receive
     the Additional Cash Compensation.

8.2  Notwithstanding the foregoing, for the avoidance of doubt and as a matter
     of utmost precaution the increase of the fair cash compensation under the
     Mandatory Offer shall be structured in a manner that, if the declarations
     described in the proviso to Section 8.1 above


                                                                            -10-

<PAGE>

     are not binding upon minority shareholders and the Original Cash
     Compensation is increased as a result of the Award Proceedings, other
     proceedings or agreements - irrespective of whether such increase occurs
     through a court ruling, an agreement amongst the parties to the relevant
     proceedings or otherwise - (the "COMPENSATION INCREASE"), the Additional
     Cash Compensation is to be credited against such Compensation Increase.
     Thus, the Additional Cash Compensation shall be deemed to be a prepayment
     on such Compensation Increase.

8.3  As long as the Purchaser complies with Sections 8.1 and 8.2, the
     undertakings of the Purchaser set forth in this Section 8 shall not prevent
     the Purchaser to enter into separate transactions with one, several or all
     minority shareholders and/or their representatives on terms and conditions
     deviating from the terms and conditions provided for in this Section 8.

9.   CONTINUED COOPERATION, CONFIDENTIALITY, PRESS RELEASES

9.1  The Parties agree to co-operate fully after the date hereof in order to
     consummate all the transactions intended by and/or envisaged in this
     Agreement. Each Party shall take such further actions, make such additional
     declarations and execute such documents as are necessary or, in the
     reasonable view of the Purchaser, appropriate to consummate the
     transactions intended by and/or contemplated in this Agreement.

9.2  The Parties shall treat the existence of this Agreement and its contents
     strictly confidential and shall make no public statements whatsoever
     concerning the existence of this Agreement and its contents.
     Notwithstanding the foregoing, it is acknowledged and agreed that (i) the
     Company and its affiliates may refer to this Agreement and describe its
     contents if and to the extent so required in order to implement the
     undertakings of the Purchaser set forth in Section 8 or by statutory law,
     regulation or order of a court, administrative agency or any other public
     authority, including, without limitation, in Form 8-K, amendments to its
     Schedule 13D, Schedule 13E-3, Form TO and other filings made pursuant to
     the U.S. Securities Exchange Act of 1934, as amended or the U.S. Securities
     Act of 1933, as amended; and (ii) each of the Sellers may refer to this
     Agreement and describe its contents to its shareholders and investors in
     accordance with past practice.

9.3  Upon execution of this Agreement, the Parties shall agree on the content
     and form of a press release with regard to the transactions and other
     agreements set forth herein. The Sellers shall not unreasonably withhold
     their consent to such or any other press releases prepared by the Purchaser
     and/or the Company. Until such press release is disseminated, the Sellers
     shall not communicate in any way with the press or any other media
     regarding this Agreement and the transactions contemplated hereby. In
     response to any unsolicited inquiry by the press or any other media
     regarding this Agreement and the transactions contemplated hereby, the
     Parties shall decline to comment. Following the dissemination of the press
     release, the Parties' only response to unsolicited inquiries by the press
     or any other media regarding the subject matter of this Agreement shall be
     that the transactions contemplated by this Agreement represent a fair
     resolution amongst the Parties with respect to the subject matter of this
     Agreement. Notwithstanding the foregoing, it is acknowledged and agreed
     that no Party shall make any adverse statements to the press or any other
     media about any other Party with respect to the subject matter of this
     Agreement.

10.  ASSIGNMENT

     None of the Sellers may not transfer any rights and obligations under or in
     connection with this Agreement without prior written consent of the
     Purchaser. The Purchaser has the right


                                                                            -11-

<PAGE>

     to only transfer its rights and obligations under this Agreement in whole
     or in part to one or more enterprises controlled by the Purchaser (each, a
     "TRANSFEREE") by way of assignment and assumption of this Agreement
     (Vertragsubernahme) (a "TRANSFER OF CONTRACT"). Upon the Transfer of
     Contract coming into effect, the Transferee fully assumes the contractual
     position of the Purchaser under this Agreement. The Sellers hereby grant
     its irrevocable consent to any Transfer of Contract. The Transfer of
     Contract shall become legally effective as of the receipt (Zugang) by the
     Sellers of a written declaration made by the Purchaser and the Transferee
     that a Transfer of Contract has occurred.

11.  LANGUAGE

     This Agreement is made in, and shall be construed in accordance with, the
     English language. In the event of a conflict between English terms and
     German terms immediately following in italics and in parenthesis in this
     Agreement, the German terms shall prevail.

12.  APPLICABLE LAW, JURISDICTION

12.1 This Agreement shall be governed by and interpreted exclusively in
     accordance with the laws of the Federal Republic of Germany with the
     exclusion of its conflict-of-laws provisions and the Convention on
     Contracts for the International Sale of Goods.

12.2 Frankfurt am Main, Germany shall be the exclusive place of jurisdiction for
     all disputes arising out of or in connection with this Agreement, provided,
     however, that the Purchaser may commence legal proceedings against the
     Sellers at any court that is competent (zustandig) for such proceedings.

13.  FEES AND EXPENSES

     Except as otherwise specifically set forth in this Agreement, the Parties
     hereto shall bear their respective expenses incurred with the preparation,
     execution and performance of this Agreement and the transactions
     contemplated therein, including all fees and expenses of their advisors and
     all fees and expenses incurred by each Party in connection with the Legal
     Proceedings.

14.  AMENDMENTS

     Any amendment or addition to this Agreement must be executed in writing,
     unless a more stringent form is required. This also applies to the deletion
     or amendment of this clause.

15.  ENTIRE AGREEMENT

     This Agreement sets out the entire agreement and understanding between the
     Parties with respect to the subject matter hereof and supersedes any and
     all earlier and current agreements, either orally or in writing, between
     the Parties.

16.  SEVERABILITY

     If one of the provisions of this Agreement is or becomes invalid or
     unimplementable, this shall not affect the validity of the remaining
     provisions. The Parties shall modify to the extent necessary or replace the
     invalid or unimplementable provision so that the effect of the modified or
     new provision corresponds as closely as possible to the intended effect of
     the invalid or unimplementable provision. In the event of an unintended
     omission in this


                                                                            -12-

<PAGE>

     Agreement, a provision shall be deemed agreed between the Parties which
     corresponds, on the basis of the purpose and the meaning of this Agreement
     and the Parties' intention, as closely as possible to the provision the
     Parties would have agreed upon had the Parties considered the matter at the
     outset.

17.  NOTICES, COMMUNICATION, EXERCISE OF RIGHTS

17.1 Any notice or other communication under this Agreement shall be effected in
     the English language and in writing and shall be delivered personally
     against confirmation of receipt or sent by "registered mail return receipt
     requested" or by an internationally recognized courier service or
     transmitted by facsimile (followed by confirmation delivered by "registered
     mail return receipt requested" or by an internationally recognized courier
     service) to the Parties at the followings addresses:

     If to the Sellers:

     Paulson & Co. Inc.
     590 Madison Avenue
     New York, NY 10022
     USA
     attn. General Counsel
     Fax no. +1 212 977 9505,

     and

     Arnhold and S. Bleichroeder Advisers, LLC
     1345 Avenue of the Americas
     New York, NY 10105
     USA
     attn.: General Counsel
     Fax no. +1 212 698 3271,

     with a copy to:

     Linklaters Oppenhoff & Radler
     Dr. Hans-Ulrich Wilsing
     Borsenplatz 1
     50667 Koln
     Germany
     Fax no. +49 221 2091 435.

     If to the Purchaser:

     Celanese Europe Holding GmbH & Co. KG
     Frankfurter Strasse 111
     61476 Kronberg i.T.
     Germany
     attn.: Management Board
     Fax no. + +49 69 305 82731 ,


                                                                            -13-

<PAGE>

     with a copy to:

     Gleiss Lutz
     Dr. Gerhard Wirth and Dr. Jan M. Bauer
     Maybachstrasse 6
     70469 Stuttgart
     Germany
     Fax no. +49 711 855 096,

     and a copy to

     Simpson Thacher & Bartlett LLP
     William R. Dougherty
     425 Lexington Avenue
     New York, NY 10017
     USA
     Fax no. +1 212 455 2502.

     The Sellers jointly on the one hand and the Purchaser on the other hand may
     change the addresses and fax numbers set forth above by giving a
     corresponding notice in accordance with this Section 17.1 indicating the
     new address and/or fax number, as the case may be, to which notices under
     this Agreement shall be delivered, provided, however, that such notice or a
     change of address shall be effective only upon receipt thereof.

17.2 Any amendments, consents, waivers, statements, declarations or notices of
     the Sellers under or in connection with this Agreement shall be validly
     made or given if made or given by Paulson. on behalf of all Sellers and
     Sellers hereby authorize Paulson to act in their name and on their behalf
     in making any and all such amendments, consents, waivers, statements,
     declarations and notices. The same shall apply to the exercise of any
     rights by the Sellers under or in connection with this Agreement.

                           [Signature Page to Follow.]


                                                                            -14-

<PAGE>

This Agreement is signed in New York, USA, on August 19, 2005 by and on behalf
of the Parties as follows:

Paulson & Co. Inc.:


By:                                     By:
    ---------------------------------       ------------------------------------
    Name:                                   Name:
    Title:                                  Title:


Arnhold and S. Bleichroeder Advisers, LLC:


By:                                     By:
    ---------------------------------       ------------------------------------
    Name:                                   Name:
    Title:                                  Title:


Celanese Europe Holding GmbH & Co. KG


By: Its general partner
    Celanese Europe Management GmbH:


By:                                     By:
    ---------------------------------       ------------------------------------
    Name:                                   Name:
    Title:                                  Title:


                                                                            -15-

<PAGE>

                                     ANNEX A

                          NAMES OF ORIGINAL PLAINTIFFS

     -    Richard Mayer

     -    Jochen Knoesel

     -    Allerthal Werke AG and Christa Gotz

     -    Carthago Value Invest AG

     -    Prof. Dr. Ekkehard Wenger

     -    Jens-Uwe Penquitt & Claus Deininger Vermogensverwaltung GbR

     -    Dr. Leonhard Knoll

     -    B.E.M. Borseninformations- und Effektenmanagement GmbH

     -    Protagon Capital GmbH


                                                                            -16-

<PAGE>

                                     ANNEX B

                             OTHER LEGAL PROCEEDINGS

I.   TENDER OFFER PROCEEDINGS (ANFECHTUNG DES AKTIENKAUFS IM RAHMEN DES
     UBERNAHMEVERFAHRENS)

<TABLE>
<CAPTION>
                                               FILE NUMBER        FILE NUMBER
  PLAINTIFF             DEFENDANT           (FIRST INSTANCE)   (COURT OF APPEAL)
-------------     -----------------------   ----------------   -----------------
<S>             <C>                         <C>                <C>
Richard Mayer   - Celanese Europe Holding     3-06 O 181/04        5 U 131/05
                  GmbH & Co. KG

                - Claudio Sonder
</TABLE>

II.  PUBLIC REGISTER PROCEEDINGS (AMTSLOSCHUNGSVERFAHREN)

1.   PUBLIC REGISTER PROCEEDINGS WITH THE KONIGSTEIN LOCAL COURT (AMTSGERICHT)

<TABLE>
<CAPTION>
           PLAINTIFFS               DEFENDANT    FILE NUMBER
--------------------------------   -----------   -----------
<S>                                <C>           <C>
Richard Mayer                      Celanese AG   80 HRB 5277
OCP Obay Capital Pool Vermogens-
   verwaltungsgesellschaft mbH
   and Protagon Capital GmbH       Celanese AG   80 HRB 5277
</TABLE>

2.   PUBLIC REGISTER PROCEEDINGS WITH THE FRANKFURT DISTRICT COURT (LANDGERICHT)

<TABLE>
<CAPTION>
                                 FILE NUMBER        FILE NUMBER
  PLAINTIFF      DEFENDANT    (FIRST INSTANCE)   (COURT OF APPEAL)
-------------   -----------   ----------------   -----------------
<S>             <C>           <C>                <C>
Richard Mayer   Celanese AG     3-16 T 25/04        20 W 425/04
</TABLE>


                                                                            -17-

<PAGE>

                                     ANNEX C

                         WAIVER LETTER (GERMAN VERSION)

                               VERZICHTSERKLARUNG

von _____________________________________, Wohnort/Sitz in ____________________,

_______________________________________________________________________________:

Mir/der von mir vertretenen Gesellschaft

     -    gehoren _______ Aktien der Celanese AG, die ich im Rahmen des
          Beherrschungs- und Gewinnabfuhrungsvertrags gegen Zahlung der
          festgelegten Abfindung einreiche;

     -    gehorten _______Aktien der Celanese AG, die ich im Rahmen des
          Beherrschungs- und Gewinnabfuhrungsvertrags gegen Zahlung der
          festgelegten Abfindung bereits eingereicht habe.

1.   Ich erklare gegenuber Celanese Europe Holding GmbH & Co. KG, dass ich/die
     von mir vertretene Gesellschaft im Zusammenhang mit dem Beherrschungs- und
     Gewinnabfuhrungsvertrag vom 22. Juni 2004

     -    keinen Antrag auf Einleitung eines Spruchverfahrens gemaB Section
          1 Nr. 1 Spruchverfahrensgesetz gestellt habe oder stellen werde oder
          einen bereits gestellten Antrag unwiderruflich und rechtsverbindlich
          zuruckgenommen habe und dass ich auf die Einleitung und Durchfuhrung
          eines Spruchverfahrens zur Bestimmung der angemessenen Barabfindung im
          Zusammenhang mit dem Ubertragungsbeschluss verzichte;

     -    Antragen nicht beitreten werde und ein Spruchverfahren
          gemaB Section 1 Nr. 1 Spruchverfahrensgesetz auch nicht in
          sonstiger Weise unmittelbar oder mittelbar fordern werde;


                                                                            -18-

<PAGE>
     -    auf eine in einem Spruchverfahren gemaB Section 1 Nr. 1
          Spruchverfahrensgesetz gerichtlich festgesetzte Abfindung oder zur
          Beendigung eines solchen Spruchverfahrens vereinbarte Abfindung
          verzichte.

_______________, den ______________ 2005

___________________________________


                                                                            -19-