I don’t want to be rude so I’ll instead suggest you look again.
The 308 is about the least reliable medium hatchback and as for buying an ex-rental – have a word with yourself.
As well as being unreliable, the 308 is a very ordinary car. It isn’t good at anything, merely adequate. They tend to be bought by people who know nothing about cars.
Damn, I said I wasn’t going to be rude…
Keep looking – if you can only afford the cheapest possible 3yr old car then consider looking for the best 4yr old car instead – you’ll get a much better car and have more choice.