The "Fokker Scourge" effects on the French was lower than on the British.
Its main consequence was that daylight "strategic" bombings were stopped and replaced by night bombings.
Against multiseats, the Fokker vs French Caudron / Farman kill ratio was around 1.5 vs 1, in favour of the Fokker (of course).
A good english written source is the Osprey Dual Nieuport 11 vs Fokker EIII book.
The Caudron G4 could fly higher than the Fokker E series WHEN THE ENGINES WORKED PROPERLY. (= not that often).
Unfortunatly, it was also used as a "fighter" to protect Voisin bombers, and results were as bad as it could be predicted.
The kill ratio between fighters was more or less equal in 1915 early 16

The French had more troubles when german two-seaters with a good rear field of fire appeared, that's how Pegoud was killed as the main tactics was a dive from rear and shooting at short range.

Note that if you fly a Spad7 in its early time, VonS 150 hp mod is a very good addition (unless if you care more on your survivability than on realism)