The Catalans installed in France in the first quarter of the XXth century, few, but concentrated in a big southwest, stemming from migrations of the work and from successive political exiles, oscillate between a Spanish republicanism and a cultural catalanisme. The plot macianiste of Prats de Mollo (1926) precipitates the construction of an identity at the same time republican and Catalan which shows itself in the support brought to the republican camp during the Spanish Civil War. The entrance to France of tens of thousand republican Catalans, later the pro-Franco victory, perpetuates an original identity which without stopping being republican also has to assert its catalanity in front of the double repression of the pro-Franco regime, without being absorbed by the French melting pot. Through the study of associations, active up to the last third of the century, we can follow the evolution of this identity cornered between loyalty to the republicans and Catalans ideals and adaptation to the society of reception.