Can Ami front arms be fit straight on to a 2cv?

Yes,
but if the knife edges are in the same position as on AKS400 and Acadiane arms, they will make the front suspension slightly softer.

They've also got larger wheel bearings, so you might want to bash the kingpins out and fit 'normal' hubs.

ken

Thanks Ken as always your answer has left me with more questions. . . . . How much softer will the suspension be considering that my car has V stiff springs? . . . Also the reason for the change is my kingpins have serious play due to worn axle so will be fitting new kingpins, do the hubs ever wear out or is it just the bushes?

Been a while since I measured some arms for comparison, but I'd doubt if it's more than about 10% to 15% reduction.
If you've got 100% ( or more) uprated springs, your fillings will still take some hammer.

Hubs don't so much wear out as get damaged during kingpin changes by folk who choose not to follow correct procedure.
Mangled threads for the lower plug is one, the recess for welch plug too loose following excessive use of a grindstone being another...

ken.

oh shit! Yeah I mangled them! Just remembered I welded penny pieces in the top last time 'cause i couldn't seal them

Thanks for your help Ken

Oops!
Found some arms and measured offset of knife edge from centre of axle.
17/114, which is 15% reduction in effective spring rate.

ken