I'm assuming you mean at the BACK of the wheel. There will be 2 'Torx' screws at the bottom of the holes (there were in my wife's 406). The holes are quite deep and the screws are difficult to see.
ive just removed mine.its a little tricky but make sure you remove or disconnect your battery first.there is 2 small holes to the rear of the housing.i used 2 very thin but long flat screwdrivers.push them both in and if you push them both to the direction of the windows feeling your way you will find that they are spring loaded.keep at it,took me quite a while,whilst gently pulling the airbag towards you.eventually it will give and removes the airbag so you can gain access to the steering wheel locking nut.im guessing your changing the indicator stalk which is the most common problem on 307's 51 onward.hope this helps.