Sounds a bit rhetorical. How information is "far-right" and "far-left"? Not much other than to expose a fallacious single-dimension scale.
How about terms like "left-socialist" or "right-nationalist"?
How about terms like "left-socialist" or "right-nationalist"?
These are the French definitions of Left and Right, and probably have nothing to do with other countries'. Based on these definitions, the Democrats are Right and Republicans are Far-right.
Whether they are good definitions, I can't say. But Mélenchon is definitely not plain Left, or Center.