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                                                                 EXHIBIT 10.1(a)

                              Dated 15 January 2004

                                   AGZ HOLDING
                                    as Parent

                                    ANTARGAZ

                            THE ENTITIES NAMED HEREIN
                                   as Lenders

                                 CREDIT LYONNAIS
                            as Mandated Lead Arranger

                                 CREDIT LYONNAIS
                                as Facility Agent

                                 CREDIT LYONNAIS
                                as Security Agent

                      ------------------------------------

                        AMENDMENT AGREEMENT RELATING TO A
     SENIOR FACILITIES AGREEMENT DATED 26 JUNE 2003 AS AMENDED AND RESTATED

                    ---------------------------------------

                             Shearman & Sterling LLP
                                      Paris

                                     [MAP]
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                                    CONTENTS

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                                                                                            PAGE
<S>                                                                                         <C>
CLAUSE
1.  INTERPRETATION.......................................................................     3
2.  AMENDMENTS TO THE FACILITIES AGREEMENT...............................................     3
3.  STATUS OF DOCUMENTS..................................................................     4
       3.1    FACILITIES AGREEMENT.......................................................     4
       3.2    FINANCE DOCUMENT...........................................................     4
4.  REPRESENTATIONS AND WARRANTIES.......................................................     4
       4.1    RELIANCE...................................................................     4
       4.2    POWERS AND CAPACITY........................................................     4
       4.3    AUTHORISATION..............................................................     4
       4.4    NO CONTRAVENTION...........................................................     4
       4.5    OBLIGATIONS BINDING........................................................     5
       4.6    CONSENTS...................................................................     5
       4.7    NO DEFAULT.................................................................     5
5.  INVALIDITY OF ANY PROVISION..........................................................     5
6.  GOVERNING LAW AND SUBMISSION TO JURISDICTION.........................................     5
       6.1    GOVERNING LAW..............................................................     5
       6.2    SUBMISSION TO JURISDICTION.................................................     5
SCHEDULE 1...............................................................................     7
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                                       ii
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THIS AMENDMENT AGREEMENT is made on [___] January, 2004

BETWEEN:

(1)   AGZ HOLDING (a company incorporated in France as a societe anonyme with
      registered number 413 765 108 RCS Paris) (the "PARENT");

(2)   ANTARGAZ (a company incorporated in France as a societe anonyme with
      registered number 572 126 043 RCS Nanterre) ("ANTARGAZ");

(3)   CREDIT LYONNAIS as mandated lead arranger (the "ARRANGER");

(4)   THE FINANCIAL INSTITUTIONS listed in schedule 1 as Lenders;

(5)   CREDIT LYONNAIS in its capacity as facility agent for the Lenders under
      the Senior Finance Documents (the "FACILITY AGENT"); and

(6)   CREDIT LYONNAIS in its capacity as agent for the Finance Parties under the
      Security Documents (the "SECURITY AGENT").

WHEREAS:

(A)   The parties to this agreement are parties to a senior facilities agreement
      dated 26 June 2003 as amended and restated by (i) an amendment and
      restatement agreement dated 2 July 2003 and (ii) an amendment agreement
      dated 1 August 2003, pursuant to which the Lenders agreed to make
      available to the Parent a EUR 220,000,000 term facility and to the
      Borrowers a EUR 50,000,000 revolving facility (the "FACILITIES
      AGREEMENT").

(B)   The parties to this agreement have agreed to enter into this agreement in
      order to amend the terms of the Facilities Agreement in the manner set out
      below.

NOW IT IS HEREBY AGREED:

1.    INTERPRETATION

      In this agreement:

      (a)   words and expressions defined in the Facilities Agreement shall,
            unless otherwise defined herein or save to the extent the context
            otherwise requires, have the same meaning when used herein;

      (b)   the provisions of Clauses 1.2 (Construction) and 1.3 (Other
            References) of the Facilities Agreement will be deemed to be set out
            in full in this agreement, but as if references in those clauses to
            the Facilities Agreement were references to this agreement.

2.    AMENDMENTS TO THE FACILITIES AGREEMENT

      Clause 11.3(b)(i) (Change of Control) shall be amended from (and
      including) the date hereof:

      (a)   by adding the following words and expressions in the end of
            paragraph (E):

            ", provided however that a Change of Control will not occur in the
            event that a third party being neither the Parent nor any of its
            Subsidiaries makes the Change of Control Offer as defined in the
            High Yield Documents and purchases all High Yield Notes tendered
            under the conditions set forth in Section 4.19, and in particular
            paragraph (g), of the High Yield Trust Deed;"

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      (b)   by adding the following words and expressions in the end of the last
            paragraph:

            "and if a Change of Control is triggered by the occurrence under the
            High Yield Documents of a Change of Control as defined in the High
            Yield Documents referred to in paragraph (E) above, the date of such
            Change of Control shall be the date the Parent or any of its
            Subsidiaries makes the Change of Control Offer under the High Yield
            Documents or purchases all or part of the High Yield Notes."

3.    STATUS OF DOCUMENTS

3.1   FACILITIES AGREEMENT

      Except as varied by the terms of this agreement, the Facilities Agreement
      will remain in full force and effect and any reference in the Facilities
      Agreement to "this Agreement", "herein", "Senior Facilities Agreement" and
      similar references or to any provision of the Facilities Agreement will be
      construed as a reference to the Facilities Agreement, or that provision,
      as amended by this agreement.

3.2   FINANCE DOCUMENT

      This agreement will constitute a Finance Document for the purposes of the
      Facilities Agreement.

4.    REPRESENTATIONS AND WARRANTIES

4.1   RELIANCE

      Each Obligor represents and warrants as set out in the following
      provisions of this clause 4 and acknowledges that each Finance Party has
      entered into this agreement and has agreed to the amendment and other
      matters effected by this agreement in full reliance on those
      representations and warranties.

4.2   POWERS AND CAPACITY

      Each Obligor has the power and capacity to enter into and comply with its
      obligations under this agreement.

4.3   AUTHORISATION

      Each Obligor has taken (or will take within any requisite time period) all
      necessary action:

      (a)   to authorise the entry into of and compliance with its obligations
            under this agreement;

      (b)   to ensure that its obligations under this agreement are valid,
            legally binding and enforceable in accordance with their terms;

      (c)   to make this agreement admissible in evidence in the courts of
            France (other than a certified translation of this agreement into
            French).

4.4   NO CONTRAVENTION

      The entry into by the Obligors, the exercise of its rights under and the
      compliance with its obligations under this agreement do not:

      (a)   contravene any law, regulation, judgment or order to which any Group
            Company is subject;

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      (b)   conflict with its constitutional documents; or

      (c)   breach any agreement or the terms of any consent binding upon any
            Group Company or any assets of any Group Company.

4.5   OBLIGATIONS BINDING

      The obligations expressed to be assumed by the Obligors under this
      agreement constitute or when executed will constitute its valid and
      legally binding obligations and are enforceable in accordance with their
      terms (subject to any applicable insolvency, bankruptcy or similar laws
      affecting creditors' rights generally).

4.6   CONSENTS

      All consents and filings required for the entry into of this agreement and
      the performance by the Obligors of their obligations hereunder have been
      obtained (or, where applicable, will be obtained within the required time
      period) and are in full force and effect.

4.7   NO DEFAULT

      (a)   No Default has occurred and is continuing.

      (b)   No event is continuing which constitutes a default under any
            agreement or document to which any Group Company is party, the
            consequence of which could reasonably be expected to have a Material
            Adverse Effect.

5.    INVALIDITY OF ANY PROVISION

      If any provision of this agreement is or becomes invalid, illegal or
      unenforceable in any respect under any law, the validity, legality and
      enforceability of the remaining provisions shall not be affected or
      impaired in any way.

6.    GOVERNING LAW AND SUBMISSION TO JURISDICTION

6.1   GOVERNING LAW

      This agreement (and any dispute, controversy, proceedings or claim of
      whatever nature arising out of or in any way relating to this agreement)
      shall be governed by, and construed in accordance with, French law.

6.2   SUBMISSION TO JURISDICTION

      For the benefit of each Finance Party, each Obligor irrevocably submits to
      the jurisdiction of the Commercial Courts of Paris (Tribunal de Commerce
      de Paris) for the purpose of hearing and determining any dispute arising
      out of this agreement and for the purpose of enforcement of any judgement
      against its assets.

Executed on the date first written above, in six (6) original copies.

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THE PARENT

AGZ HOLDING

By:___________________________

ANTARGAZ

By:___________________________

ARRANGER, LENDER, FACILITY AGENT AND SECURITY AGENT
------------------------------------------------------
CREDIT LYONNAIS

By: Jerome Del Ben

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                                   SCHEDULE 1

                                     LENDERS
                              Credit Lyonnais S.A.
                                   BNP Paribas
                         Credit Industriel et Commercial
                            Deutsche Bank AG, London
                              ING Bank (France) SA
                       Sumitomo Mitsui Banking Corporation
                                    WestLB AG
                             AIB Capital Markets plc
                                Bank of Scotland
                                    CDC IXIS
                      Compagnie Financiere du Credit Mutuel
                         Credit Agricole d'Ile de France
                                 Credit du Nord
                          IKB Deutsche Industriebank AG
                      Lloyds TSB Bank PLC, Brussels Branch