Le plus grand groupe de rock francais, and we'll pretty much agree. Ange's completely original and unique take on the "progressif" is most definitely and definitively French. Led by vocalist Christian Decamps.
Refused entry to the UK, former Soft Machiner Daevid Allen remained in France and started Gong. Their earliest recordings take a cue from Barrett-era Floyd, but the hypnotic Continental Circus is underrated. Always maintaining a fluid line-up, things congealed enough for the classic Radio Gnome trilogy of albums. By 1975 however, Allen and Smyth headed down to Majorca, and the silliness subsided. Eventually Pierre Moerlen took over the helm, veering off into a full-fledged fusion outfit.
Founded by drummer Gilbert Artman, Lard Free was similar to Richard Pinhas' Heldon; French, unconventional, experimental, but, incredulously, a rock band. Later albums would draw parallels to the cosmic side of the ubiquitous "krautrock" of Germany. Artman would simultaneously lead the massive performances of Urban Sax.
Perhaps most idiosyncratic of all progressives, Christian Vander's Magma documented the other-worldly parables of the planet Kobaia. The early side project Univeria Zekt album The Unamables is great introduction, but even their first two albums wouldn't prepare the world for the completely over the top epic Mekanik Destruktiw Komanndoh. Sung in Vander's self-created language, Magma's music a cross between Carl Orff, John Coltrane and some dark-ass heavy metal!