what size socket do I use to remove the nut holding the wheel bearing in my 206 I have a32mm and 38mm

When l was selling tools the most common sizes were ,30,32&36 mm

l will say 32 mm.
Although l do not own a 206, the bolts on the 104, 204, 304, 205, 305, 405 that l have owned & currently own is a 32 mm bolt. You may be able to use a 1 1/4 inch 6 sided socket.it is almost the same as 32mm.

The easiest way to loosen this bolt is to have the tyre still on the car. Parked on cement, not gravel. Emergency hand brake ON.
The bolt is put on with 250 Nm of force. This means u probably need a long breaker bar & a 6 point 1/2'' socket. Do not use ur favourite socket wrench & a metal pipe for length. You will ruin ur wrench/spanner, under the stress of 250 Nm = 185 foot pounds. Gti models even tighter! Automatic transmissions EVEN tighter!

PS: Upon refitting, A new bolt is always recommended, but l never do this unless the old bolt is rounded-off even slightly, or rusty.