Some people know about the French ERAC (Engin de Reconnaissance Amphibie de Combat), not to be confused with Engin de Réaction Anti-Chars:
It's an amphibious light tank from the early '60s, but apparently it didn't end with this vehicle. New photos have been added somewhat recently on chars-francais.net of a second, albeit similar vehicle:
No additional information is revealed, but the mounted gun is quite obviously larger than on the first one. Both vehicles are labeled "ERAC 105mm", yet the website claims the gun to be the 90mm DEFA D 914.