What about suspending the opposition procedure?
Obtaining a patent in France: the opposition procedure

(see article R613-44-10 du CPI ).

The examination phase and the decision phase of the opposition procedure may be suspended if a third party has lodged an action claiming ownership of the patent or if an invalidity action is pending against the patent.

The examination phase and the decision phase may be suspended ex officio by INPI if additional information and elements are awaited that could have an impact on the file.

The parties may also request a stay of proceedings, but only during the investigation phase, and they must do so by mutual agreement.

The suspension obtained will be for 4 months, renewable twice.