try rocking/turning the wheel while turning the key.
Try using a spare key if that doesn't work you need a locksmith.
Try turning steering wheel slightly while you do it.
you wont be able to turn the steering wheel so easily if you dont fix it you wont be able to turn it at all
try moveing the steering wheel it could be in the lock position so while you trun the wheel trun your key at same time
put the kay in the ignition and then turn the car on then turn the wheel. im ean its not rocket sciene...BIG HAIRY
Try turning the steering wheel either to the right or left while attempting to turn the key
Your key could be worn. Try moving your steering wheel while turning the ignition. If the locked steering is in a bind the key will not turn over.
steering wheel in locked positon try moving it a little either way and the key should turn. The steering wheel has a locking device that wont let the key turn if the wheel is not free or you have the Wrong key
Try turning the steering wheel whilst turning the key, most peugeots have a built in steering lock.
Step on brake first. Turn steering wheel slightly to remove tension on key.
You could try turning your steering wheel both directions to release pressure then turn.
make sure the steering wheel isn't locked