If the windows go down then you can rule out a problem with the roof switch, so the issue is most likely with the roof mechanism itself. The roof contains a number of sensors, wires and modules so you'll need a proper code reader to identify which one of these is not responding. The best place to start is by resetting the roof mechanism, which can be done via a switch under the right-hand front headlight, but only with a diagnostic scanner. You'll need to take the car to a Peugeot dealer or specialist to get the codes read but the good news is that once the source of the problem is found, repairs are rarely expensive.