To my knowledge, only one of the three EQ novels has been translated into French That's "A room to die in", translated into "Une chambre pour mourir", a "literal" translation. Actually, "chambre" is a "bedroom", not just any old unspecified room, which would be "une pice"...

Apart from those two untranslated EQ novels, many Vance mysteries remain to be translated into French :
Take my Face (The Flesh Mask) - 1956
Bird Island (Bird Isle - Isle of Peril) - 1957
Strange People, Queer Notions - 1958
The Man in the cage -1959
The Dark Ocean - 1966
The Deadly Isles - 1967

Who knows, one day, a French publisher will be interested ? But I doubt it.