The French Union (French: Union française) was a political entity created by the French Fourth Republic to replace the old French colonial system, colloquially known as the "French Empire" (Empire Français). It was the formal end of the "indigenous" (indigène) status of French subjects in colonial areas.
The French Union had five components:
The French Union was established by the French constitution of October 27, 1946 (Fourth Republic). Under it, it was said that there were no French colonies, but that metropolitan France, the overseas departments, and the overseas territories combined to create a single French Union, or just one France.
The goal of this union was "assimilation of the overseas territories into a greater France, inhabited by French citizens, and blessed by French culture." Whereas the British colonial system had local colonial governments which would eventually evolve into separate national governments; France wanted to create a single government under a single French state.
This French Union had a President, a High Council and an Assembly. The President was the President of the Republic. The Assembly of the Union had membership from the Council of the Republic, from the National Assembly and from regional assemblies of the overseas territories and departments but ultimately had no power. The High Council ultimately only met three times, first in 1951. The Assembly was the only actually functioning institution that could manage legislation within the overseas territories.
In reality, the colonial areas had representation but all power remained in the French Parliament and thus was centralized. The colonies had local assemblies but these had only limited local power. Instead, various natives of the overseas territories in metropolitan France grew into a group of elites, known as evolués.
On January 31, 1956, hoping to having peace in Algiers, the system changed, abandoning assimilation in favor of autonomy, allowing territories to develop their own local government and to eventually gain their independence. This would not succeed however and in 1958 the French Union was replaced by the French Community by Charles de Gaulle's Fifth Republic wherein France was now a federation of states with their own self-government.