They'd have to resell them abroad though, the local market would be pretty much saturated, no?

It's not difficult to get from Paris to Barcelona and back, with or without a bike.

If I need to offload an ebike from Paris, I could think of closer countries that would value them higher!

Why would you buy a bike from a reseller for $0 + profit when you can get one the with a government subsidy for $0?

Isn't that true of any subsidy? If 40% of my bike is subsidized, I only need to buy and resell that bike for greater than 60% of the purchase price.

I bet you'd get less resellers, but you'd definitely still get a lot of them.

That is true with any amount of subsidy. And yes, and people can use e.g. welfare payments to buy cigarrettes and booze. That is in itself not an argument against welfare payments.