Article 1098 of the French Civil Code
If a spouse has made to his or her spouse, within the limits of article 1094-1, a gift in property, each of the children who are not descended from both spouses shall have, as far as he or she is concerned, unless the disposing spouse wishes otherwise and unequivocally, the option of substituting for the execution of this gift the relinquishment of the usufruct of the share of the estate…