A great majority comes North Africa the Magrheb : Algeria (which has been French before its independence in 1962), Morocco, Tunisia.
Many come also from Africa as Sénégal, where French were very present(it has been a French colony) and some other countries from Africa . This comes from the slavery period. Some slave ships were leaving from the Nantes harbour. But many other African nationalities are present too.
There are many people from the French Antigua (Guadeloupe, Martinique, Guyana), but they are French.
there are also many Portuguese who ran away during the dictatorial government (Spanish as well, and Italians). This was mainly during the first and second World War .