While Communists were certainly the backbone/largest component of the French Resistance within France, describing it as "almost entirely" Communist is massively overstating the case. This starts from the basic caveat that France fell in June 1940 but French Communists, following Moscow's party line, tended to not be involved with overt resistance until June 1941, when Germany invaded the USSR. The second massive caveat is that French resistance outside of Metropolitan France was largely affiliated with the Free French movement and the decidedly uncommunist Charles de Gaulle.

It wouldn't be a controversial statement to say that the French Resistance 1941-1944 inside Metropolitan France was spearheaded by Communist partisans and that the Communists were at the forefront of Resistance activity, but the Resistance also contained factions discontented with the Germans and the Vichy government from around the political spectrum.