Given your locale am I correct that you are targeting French, Portuguese, and Spanish audiences in Europe?

If so my experiences are not particularly germane: I translated my sites into French (as Canada's second official language) and Spanish (targeting audiences in the Americas).

European visitors in those languages are more a bonus than target audiences.

From the get go my Spanish AdSense has been great, French rather ho hum. In relative terms compared to my English sites Spanish is almost a third better, French over a third worse.

Actually I have a worldwide audience and both Spanish and Portuguese visitors are mainly from the Americas. It is surprising the difference in results - may be an industry related thing.