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                                                                   EXHIBIT 10.15

                       CANADIAN TAX CO-OPERATION AGREEMENT

THIS AGREEMENT is made as of May 8th, 2002.

BETWEEN:

                  TRIZECHAHN OFFICE PROPERTIES LTD.
                  a corporation organized under the laws of the
                  Province of New Brunswick
                  ("THOPL")

                                     - and -

                  TRIZEC PROPERTIES, INC.
                  a corporation organized under the laws
                  of Delaware
                  ("TRIZEC PROPERTIES")

RECITALS:

A.    Substantially all of the shares in the capital stock of Trizec Properties
      are indirectly owned by THOPL;

B.    The manner in which the Trizec Properties Parties undertake activities
      will affect the Canadian tax consequences to the THOPL Parties;

C.    The Trizec Properties Parties have historically conducted their business
      operations having regard to the Canadian tax consequences of their actions
      to relevant THOPL Parties and wish to continue to do so in a manner
      consistent with past practice once Trizec Properties becomes a publicly
      traded corporation; and

D.    The parties wish to implement the terms of this Agreement in a manner
      which is not burdensome on the effective management of the Trizec
      Properties Parties and which allows Trizec Properties' management to
      operate in a manner which is in the best interests of all Trizec
      Properties shareholders.

      THEREFORE, in consideration for the relevant THOPL Parties agreeing to
participate in transactions pursuant to which it is expected that Trizec
Properties will become a publicly traded corporation and for other for good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties agree as follows:

                                    ARTICLE 1
                                 INTERPRETATION

1.1   DEFINITIONS

      For purposes of this Agreement, the following terms shall have the
      meanings set forth below:

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      "CANADIAN TAX" means any tax imposed under the Canadian Tax Statutes;

      "CANADIAN TAX STATUTES" means the Income Tax Act (Canada) (and any
      regulations thereunder) and each corresponding provincial taxation statute
      (and any regulations thereunder);

      "CANADIAN CORPORATION" means any corporation or company incorporated or
      otherwise formed under the laws of Canada or any province or territory
      thereof;

      "TRIZEC CANADA" means Trizec Canada Inc.

      "CONTROLLED TRIZEC PROPERTIES PARTY" means Trizec Properties and any
      corporation, company, partnership, trust or other entity, organization or
      relationship of any kind controlled by Trizec Properties, alone or
      together with any other entities controlled by Trizec Properties;

      "NON-CONTROLLED TRIZEC PROPERTIES PARTY" means, at any time, any
      corporation, company, partnership, trust or other entity, organization or
      relationship of any kind in which Trizec Properties, alone or together
      with any entities controlled by Trizec Properties, has an ownership
      interest representing, at such time, 10% or more of all ownership
      interests in such party but which is not a Controlled Trizec Properties
      Party;

      "THOPL PARTY" means THOPL, any Canadian Corporation controlled by or
      controlling THOPL and any Canadian Corporation controlled by a Canadian
      Corporation that controls THOPL and that, at any time on or after the date
      hereof, directly or indirectly has or has had a direct or indirect
      ownership interest in, Trizec Properties (through share ownership or
      otherwise), but excluding PM Capital Inc. or any other Canadian
      Corporation holding an ownership interest in Trizec Canada, unless such
      corporation is a successor corporation to Trizec Canada;

      "TRIZEC PROPERTIES PARTY" means any one of Trizec Properties, a Controlled
      Trizec Properties Party or a Non-Controlled Trizec Properties Party.

1.2   CONTROL

      A party is "controlled" by (i) any person holding, directly or indirectly,
voting securities which carry votes sufficient, if exercised, to elect a
majority of the board of directors, trustees, managers or other governing body
of the controlled party, and (ii) any person who otherwise has the ability to
control and direct the business and operations of such controlled party and the
terms "control" and "controlling" shall have corresponding meanings.

1.3   REFERENCES TO CANADIAN TAX STATUTES

      Any reference to any of the Canadian Tax Statutes, any provision thereof
or any regulation thereunder shall be deemed to include a reference to any
amendment thereto, and to include a reference to any comparable provision of any
other statute or regulation now or hereafter enacted by the government of Canada
or any province, territory or municipality therein to substantially similar
effect.


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1.4   REFERENCES TO NON-CONTROLLED TRIZEC PROPERTIES PARTIES

      Wherever in this Agreement there is a reference to a requirement that
Trizec Properties "endeavour to cause" a Non-Controlled Trizec Properties Party
to take or not to take certain action, it means that Trizec Properties will use
its best efforts on a commercially reasonable basis to do so.

1.5   HEADINGS

      The division of this Agreement into Articles and Sections and the
insertion of an index and headings are for convenience of reference only and
shall not affect the construction or interpretation hereof. The terms "THIS
AGREEMENT", "HEREOF", "HEREUNDER" and similar expressions refer to this
Agreement and not to any particular Article, Section, paragraph or other portion
hereof and include any agreement supplemental hereto. Save as expressly provided
herein, references herein to Articles and Sections are to Articles and Sections
of this Agreement.

1.6   EXTENDED MEANINGS

      Words importing the singular number only shall include the plural and vice
versa, and words importing any gender shall include all genders. The term
"including" means "including without limitation".

1.7   SEVERABILITY

      In the event that one or more of the provisions contained in this
Agreement shall be invalid, illegal or unenforceable in any respect under any
applicable law, the validity, legality or enforceability of the remaining
provisions hereof shall not be affected or impaired thereby.

                                    ARTICLE 2
                           OBLIGATIONS OF THE PARTIES

2.1   MINIMIZATION OF CANADIAN TAX

Trizec Properties shall not, and shall cause each Controlled Trizec Properties
Party and endeavour to cause each Non-Controlled Trizec Properties Party to not,
undertake any course of action in the operation of its business or otherwise
which could reasonably be expected to have adverse consequences to a THOPL Party
under the Canadian Tax Statutes which could reasonably be expected to be
material in the circumstances; provided however that this provision shall not
require a Trizec Properties Party to breach any provision of any contract in
existence at the date of this Agreement.

2.2   CANADIAN TAX REPORTING INFORMATION

      At the request of a THOPL Party, Trizec Properties (at its own expense)
will and will cause any Controlled Trizec Properties Party and will endeavour to
cause any Non-Controlled Trizec Properties Party to provide, on a timely basis,
information considered necessary by the THOPL Party, acting reasonably, to
permit any relevant THOPL Party to comply with its reporting requirements or
make calculations or for any other purpose that relates to the taxation


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under the Canadian Tax Statutes of a relevant THOPL Party, in each case for
fiscal years of a relevant THOPL Party ending on or before December 31, 2007. A
relevant THOPL Party shall be entitled to make copies of such information and to
retain such information indefinitely. The provisions of this Section 2.2 shall
survive the termination of this Agreement, but only insofar as information
relates to fiscal years of a relevant THOPL Party ending on or before December
31, 2007.

2.3   LIMITATION ON OBLIGATIONS

      Nothing in this Agreement shall be construed so as to require any Trizec
Properties Party to take any action that in the reasonable opinion of Trizec
Properties will endanger its status as a "Real Estate Investment Trust" for
purposes of the Internal Revenue Code (1986) as amended.

2.4   COMMUNICATIONS

Trizec Properties shall communicate with the relevant THOPL Parties (directly or
through another Trizec Properties Party) on a regular, quarterly basis (or more
frequently if requested by THOPL) so that the relevant THOPL Parties are made
aware of matters which may have an effect on the treatment of the relevant THOPL
Parties under the Canadian Tax Statutes.


2.5   CONFIDENTIALITY

      THOPL shall, and shall cause each of the relevant THOPL Parties to, keep
confidential all information and documentation relating to the business of the
Trizec Properties Parties and other information provided to any of them by a
Trizec Properties Party pursuant to this Agreement, other than:

      (i)   information or documentation in the public domain through no fault
            or act of THOPL or the relevant THOPL Party;

      (ii)  disclosure to a taxing authority necessary to permit any relevant
            THOPL Party to comply with its reporting requirements under the
            Canadian Tax Statutes;

      (iii) such disclosure to a taxing authority as a relevant THOPL Party
            reasonably believes is necessary or beneficial in connection with
            the review of its tax affairs by, or the contestation of its tax
            affairs with, a taxing authority having jurisdiction over such
            relevant THOPL Party; and

      (iv)  information otherwise required to be disclosed by law, and in such
            case prior written notice shall be provided to Trizec Properties;

      (v)   disclosure by a relevant THOPL Party to its professional advisors
            (including auditors) with respect to matters contemplated by this
            Agreement provided such Persons use such information only with
            respect to matters contemplated by this Agreement and are advised of
            the requirement of confidentiality under this Agreement.


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                                    ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

3.1   REPRESENTATIONS AND WARRANTIES OF TRIZEC PROPERTIES

      Trizec Properties represents and warrants as follows to THOPL and
acknowledges and confirms that THOPL is relying upon such representations and
warranties:

(a)   CORPORATE STATUS. Trizec Properties is a corporation duly incorporated and
      validly existing under the laws of Delaware.

(b)   CORPORATE POWER AND AUTHORITY. Trizec Properties has full corporate power
      and authority to enter into this Agreement, and to do all acts and things
      and execute and deliver all documents as are required hereunder to be
      done, observed or performed by it in accordance with the terms thereof.

(c)   AUTHORIZATION AND ENFORCEABILITY. This Agreement has been delivered by
      Trizec Properties and constitutes a valid and legally binding obligation
      of Trizec Properties enforceable against it in accordance with its terms,
      subject to applicable bankruptcy, insolvency and other laws affecting the
      enforcement of creditors' rights generally.

(d)   CONFLICT WITH CONSTATING DOCUMENTS AND AGREEMENTS. Neither the execution
      and delivery of this Agreement nor compliance by Trizec Properties with
      the terms, conditions and provisions hereto, will conflict with or result
      in a breach of any of the terms, conditions or provisions of:

      (i)   the constating documents or by-laws of Trizec Properties or any
            unanimous shareholders' agreement relating to it;

      (ii)  any resolution of the shareholders, directors or any committee of
            directors of Trizec Properties;

      (iii) in any material respect, any agreement, instrument or arrangement to
            which Trizec Properties is now a party or by which it, or its
            properties are, or may be, bound, or will constitute a default
            thereunder; or

      (iv)  any judgment or order, writ, injunction or decree of any court.

(e)   NO OTHER AUTHORIZATION OR CONSENTS NECESSARY. No action (including,
      without limitation, the giving of any consent, licence, right, approval,
      authorization, registration, order or permit) of, or filing with, any
      governmental or public body or authority is required to authorize, or is
      otherwise required in connection with, the execution, delivery and
      performance by Trizec Properties of this Agreement or in order to render
      this Agreement legal, valid, binding or enforceable except those actions
      which have been obtained or filings which have been made.


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3.2   REPRESENTATIONS AND WARRANTIES OF THOPL

      THOPL represents and warrants as follows to Trizec Properties and
acknowledges and confirms that Trizec Properties is relying upon such
representations and warranties:

(a)   CORPORATE STATUS. THOPL is a corporation duly continued and validly
      existing under the laws of Province of New Brunswick.

(b)   CORPORATE POWER AND AUTHORITY. THOPL has full corporate power and
      authority to enter into this Agreement, and to do all acts and things and
      execute and deliver all documents as are required hereunder to be done,
      observed or performed by it in accordance with the terms thereof.

(c)   AUTHORIZATION AND ENFORCEABILITY. This Agreement has been delivered by
      THOPL and constitutes a valid and legally binding obligation of THOPL
      enforceable against it in accordance with its terms, subject to applicable
      bankruptcy, insolvency and other laws affecting the enforcement of
      creditors' rights generally.

(d)   CONFLICT WITH CONSTATING DOCUMENTS AND AGREEMENTS. Neither the execution
      and delivery of this Agreement nor compliance by THOPL with the terms,
      conditions and provisions hereto, will conflict with or result in a breach
      of any of the terms, conditions or provisions of:

      (i)   the constating documents or by-laws of THOPL or any unanimous
            shareholders' agreement relating to it;

      (ii)  any resolution of the shareholders, directors or any committee of
            directors of THOPL;

      (iii) in any material respect, any agreement, instrument or arrangement to
            which Trizec Properties is now a party or by which it, or its
            properties are, or may be, bound, or will constitute a default
            thereunder; or

      (iv)  any judgment or order, writ, injunction or decree of any court.

(e)   NO OTHER AUTHORIZATION OR CONSENTS NECESSARY. No action (including,
      without limitation, the giving of any consent, licence, right, approval,
      authorization, registration, order or permit) of, or filing with, any
      governmental or public body or authority is required to authorize, or is
      otherwise required in connection with, the execution, delivery and
      performance by THOPL of this Agreement or in order to render this
      Agreement legal, valid, binding or enforceable except those actions which
      have been obtained or filings which have been made.


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                                    ARTICLE 4
                            DISPUTES AND ARBITRATION

4.1   ARBITRATION OF DISPUTES

      If any dispute or question shall arise between THOPL and Trizec Properties
arising out of or relating to this Agreement or any part thereof, including, but
not limited to, its formation, execution, validity, application, interpretation,
performance, breach, termination or enforcement or the respective rights and
obligations of THOPL and Trizec Properties hereunder (a "DISPUTE") the Dispute
shall be referred to a sole arbitrator for arbitration. The arbitrator shall be
an individual who is chosen by mutual agreement of THOPL and Trizec Properties.
If THOPL and Trizec Properties are unable to agree upon an arbitrator within
thirty (30) days of a Dispute, THOPL or Trizec Properties may apply to a judge
of the Ontario Superior Court to appoint an arbitrator in accordance with
Article 11(3)(b) of the Model Law (as defined in section 4.3).

4.2   LAW GOVERNING ARBITRATION

      All issues referred to arbitration (including the scope of the agreement
to arbitrate, the law relating to enforcement of the agreement to arbitrate, any
relevant limitation periods, the law governing the procedure of the arbitration,
the law relating to available remedies, set-off claims, conflict of laws rules
and claims to costs and interest) shall be governed by the substantive laws of
the Province of Ontario. The parties hereto agree that this arbitration
agreement is governed by the International Commercial Arbitration Act (Ontario),
R.S.O. 1990, c.I.9, as amended, that the subject matter of this arbitration
agreement relates to more than one country and the parties to this arbitration
agreement have their places of business in different countries. Unless otherwise
agreed by THOPL and Trizec Properties, the place of the arbitration shall be
Toronto, Ontario and any hearing in the course of the arbitration shall take
place in Toronto, Ontario in the English language.

4.3   AWARD BINDING

      Any award or determination, including determinations on interim or
interlocutory matters, of the arbitrator shall be final and binding and there
shall be no appeal or recourse therefrom, subject only to the provisions of the
International Commercial Arbitration Act (Ontario) and the Model Law on
International Commercial Arbitration adopted by the United Nations Commission on
International Trade Law on June 21, 1985 (the "Model Law"). Except as
specifically provided in the International Commercial Arbitration Act (Ontario)
and the Model Law, all issues arising in connection with a Dispute, including
interlocutory and interim matters, shall be resolved by the arbitrator and
through the arbitration process and shall not be resolved by application to the
Superior Court of Justice for the Province of Ontario or to any other court.

4.4   CONFIDENTIALITY

      The arbitration shall be kept confidential and its existence and any
element of it (including submissions and any evidence or documents presented or
exchanged) shall not be disclosed, except as required by law, beyond the
arbitrator, THOPL and Trizec Properties (including their auditors and insurers),
their counsel and any person necessary to the conduct of


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the arbitration. No individual shall be appointed as an arbitrator unless he or
she agrees in writing to be bound by this confidentiality provision.

4.5   EXPERTS

      The arbitrator may, without the consent of THOPL and Trizec Properties,
appoint any expert.

4.6   PROCEDURES

      The procedures and timetable for the conduct of the arbitration shall be
established by the arbitrator after receiving and considering submissions
regarding the procedures and timetable from THOPL and Trizec Properties and
having due regard for their desire that the overriding objective in establishing
the procedures and timetable be that the Dispute be resolved as expeditiously as
is reasonably possible.

                                    ARTICLE 5
                                  MISCELLANEOUS

5.1   BENEFIT OF THE AGREEMENT

      This Agreement shall enure to the benefit of and be binding upon the
successors and permitted assigns of Trizec Properties and the successors and
permitted assigns of THOPL.

5.2   NOTICES

      All notices, requests, demands or other communications to or from the
parties hereto shall be in writing and shall be given by overnight delivery
service, by hand delivery or by telecopy to the addressee as follows:

(a) to Trizec Properties or any Trizec Properties Party:

      1114 Avenue of the Americas
      New York, NY 10036
      U.S.A.

      Attention:   Chief Financial Officer
      Fax No.:  212-382-9359

(b) to THOPL or any relevant THOPL Party:

      BCE Place, 181 Bay Street
      Suite 3900, P.O. Box 800
      Toronto, ON M5J 2T3

      Attention: Chief Financial Officer
      Fax No.:  416-364-5491


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or at such other address or to such other individual as either party may
designate by notice to the other party.

5.3   AMENDMENT AND WAIVER

      This Agreement may be modified or amended and a waiver of any breach of
any term or provision of this Agreement shall be effective only if Trizec
Properties and THOPL so agree in writing. A waiver of any breach of any term or
provision of this Agreement shall be limited to the specific breach waived.

5.4   GOVERNING LAW

      This Agreement shall be governed by and construed in accordance with the
laws of the Province of Ontario. Subject to the provisions of Article 5
regarding the parties agreement to submit disputes to arbitration, Trizec
Properties and THOPL each agrees that any legal suit, action or proceeding
arising out of this Agreement may be instituted in the courts of Ontario, and
each of Trizec Properties and THOPL hereby accepts and irrevocably submits to
the non-exclusive jurisdiction of said courts and acknowledge their competence
and agree to be bound by any judgment thereof.

5.5   FURTHER ASSURANCES

      Each of Trizec Properties and THOPL shall promptly cure any default in its
execution and delivery of this Agreement and agree that it will from time to
time at the reasonable request of the other party hereto execute and deliver
such documents and instruments and take such further action as may be required
pursuant to the terms hereof to accomplish the purposes of this Agreement.

5.6   TERMINATION

      This Agreement and the obligations of the parties hereunder shall
terminate at the earlier of (i) the end of the day on which Trizec Properties
ceases to be a "foreign affiliate" (for purposes of the Canadian Tax Statutes)
of a THOPL Party and (ii) the end of the day on December 31, 2007, provided,
however, that the obligations of Trizec Properties under Section 2.2 and the
obligations of THOPL under Section 2.5 which shall survive the termination of
this Agreement for a further period of 10 years.


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      IN WITNESS WHEREOF the parties hereto have executed this Agreement.

                                          TRIZECHAHN OFFICE PROPERTIES LTD.

                                          By: /s/ Robin A. Campbell
                                              ---------------------------------

                                          By: /s/ Colin Chapin
                                              ---------------------------------


                                          TRIZEC PROPERTIES, INC.

                                          By: /s/ Christopher Mackenzie
                                              ---------------------------------

                                          By: /s/ Gregory H. Hanson
                                              ---------------------------------


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