Could be the MAF sensor needing a clean? Super easy to DIY if so (YouTube etc for exact model and details, but you basically need a screwdriver and a can of electrical contact cleaner), and if that doesn't change it at least you haven't spent £££ on garage labour to find it out.
Any know of a Renault specialist? Ideally east. Partners car is really gutless and needs crazy revving to get it going.