Subject: Contractual revocation indemnity

<PAGE>

AGZ HOLDING                                           EXHIBIT 10.15

Mr. Francois VARAGNE

                                                     22 rue Octave Feuillet

                                                     75016 PARIS

                                                      May 15, 2002

Subject: Contractual revocation indemnity

Sir,

Following the approval granted by the Board of Directors of AGZ Holding on May

14, 2002, we hereby undertake to pay you a contractual indemnity in the event of

revocation of your functions in Antargaz under the conditions specified below.

In the event of revocation of your functions as Chairman of the Board of

Directors of Antargaz, AGZ Holding will pay you a revocation indemnity under the

following conditions:

      -      The indemnity will be paid to you in the event of revocation of your

            functions as Chairman of the Board of Directors and General Director

            of Antargaz.

      -      The revocation must not be based on severe or gross negligence in

            the performance of your func