Mexes could take Fifa action
The French outfit have received an offer from Manchester United - which is almost double Roma's approach - which is around é¼8 million.
Mexes has, though, rejected Old Trafford in favour of Stadio Olimpico and he seems set on a move to the Italian capital.
"Franco Baldini, one of the AS Roma officials, has agreed a four-year contract with Philippe Mexes," said Olivier Jouanneaux.
Jouanneaux insists that Auxerre are going back on a previous agreement to let his client depart the club and now they are ready to get Fifa involved in the matter.
"For a while there was an agreement between AJA and Philippe Mexes over a departure in June 2004.
"Unfortunately the player and his former employer can't find an agreement on the financial details of that departure.
"So, Philippe Mexes asked the Fifa committee to settle the disputes, to resolve the different financial questions about that international transfer."