Not Lyon nor south but France is the country.
Where Am I? Game
If it is not in the south, then the river is probably the Seine?
That would be insane...
Maybe near Rouen?
River is indeed Seine, city is not Rouen but it isn't very far.
Quoting hennaonthetrek
River is indeed Seine
Then I go for the simple answer: Paris?
Simple is often correct and so it is now also, your turn theo1006 
Thanks, Henna.
Where did we see all these vehicles in one place?
Ooooh. I used to fly helicopters and that is a Sud Aviation Alouette. Lovely.
Its registration and flag suggest it's Swiss?
Quoting AndyF
Its registration and flag suggest it's Swiss?
Could be, I am not familiar with regstration marks of helicopters. But we photograped it not in Switzerland.
I went looking for museums with a vehicle collection. I found one in Speyer, Brooklands and in Beaune. Based on the picture with the abarth, I'm going with the one in Beaune: Chateau Savigny-les-Beaune