The sentence pronounced abroad is, by the effect of the international convention or agreement, directly and immediately enforceable on national territory for the part that remained to be served in the foreign State.
However, where the penalty imposed is, by its nature or duration, more severe than the penalty provided for by French law for the same acts, the criminal court of the place of detention, seised by the public prosecutor or the convicted person, will substitute the penalty that corresponds most closely to French law or reduce this penalty to the maximum legally applicable. It will accordingly determine, depending on the case, the nature and, within the limit of the part that remained to be served in the foreign State, the length of the sentence to be served.
.