Disconnect battery negative side. Leave for 20 mins, then jack up car and support both sides.
Underneath the car on the side closest to you there are two rubber bungs, remove them and that will reveal two nuts - 13mm iirc. And then there are two more not covered under the exhaust heat shield towards the centre of the car. Again 13mm.
Now, before you start yanking at the chair to pull it out, on both seats you'll have two connectors. One is for the airbag, the other is for the seat belt pre tensioner. These two plugs disconnect easily enough, then the seat will be free to lift back.
When putting the new seats in - i presume buckets - you can use 3.3 ohm resistors in the two plugs to avoid dashboard lights
http://www.cliosport.net/forum/showthread.php?t=109205&highlight=airbag handy guide there.
Use the original 13mm nuts you took off earlier with the new bolts and jobs a good one!