Some cars produced before 2011 were not designed to run on E10 fuel, which contains a higher proportion of ethanol and while it will not affect how the engine operates, it can cause issues with rubber and plastic components which were not designed to deal with the higher ethanol content. Although the specified fuel for your Peugeot is E5, the goverment's E10 compatibility service here - check-vehicle-compatibility-e10-petrol.service.gov...r - states that all Peugeots with petrol engines manufactured since January 2000 are compatible with E10.