Was the Latin Monetary Union a Franc Zone?

In 1865, a monetary union was formed between Belgium, France, Italy and Switzerland (Greece would follow three years later). According to the Treaty (which created what the press called l‘Union latine or Latin Union, but which was officially known as Convention de 1865) the member states shared a common monetary base consisting of specie. The agreement, established in the first instance for fifteen years and renewable (it would be indeed renewed in 1880) provided for the circulation throughout the Union of gold and silver coins issued independently by all participants. The Latin Union’s coins were identical in all respects but the print which indicated the country of origin. The agreement was substantiated by the commitment on behalf of each national Treasury to accept in payment the coins of any other member state.