A 1.2L is meant for city driving rather than country driving, and it's just fine for that. There are much better engines available for the C3 aircross, so you just didn't get one that was appropriate I'm afraid.
For some reason rental companies always seem to try to give you underpowered cars no matter where, I'm not sure why since they do have better ones which are also more expensive so they're not losing money renting them.