My wife and I are married under the community of property regime. We haven't been living together for several years and would like to have this legal separation declared by a judge. If we ever decide to live together again, what would be the consequences?

The resumption of cohabitation puts an end to the legal separation and re-establishes the previous effects attached to the marriage, with the exception of the matrimonial property regime, the separation of property being maintained (art. 305, al. 1 and 3 C. civ.).
Please note: for this situation to be known and opposable to third parties, the reconciliation must be recorded through a notarial act or declared to the civil registrar. A mention is then made in the margin of the marriage certificate and the spouses' birth certificates (art. 305 al. 2 C. civ. and 1130 C. proc. civ..).