Usually that is caused by the brake light switch becoming "out of adjustment," but sometimes it can be caused by a defective brake light switch.
Possibly a defective brake light swith stuck closed.
check little switch under your brake pedal....... and check brake fluid. This was the problem on daughters 206 . Topped up brake fluid on now ok.
probably the brake light switch on the pedal if none are working at all
how two change my front head lights on a peugeot 206
there is a wire and plug jus under your glovebox in the pasenger side footwell. if you plug that back in the lights will work properly again.
Brake it
Passions - 1999 1-206 was released on: USA: 19 April 2000
engine fault/oil low/water low .brake fault
The Early Show - 1999 9-206 was released on: USA: 16 October 2008
Payne - 1999 Trouble in Room 206 1-6 was released on: USA: 14 April 1999
If the back lights on a Peugeot 206 are not working, make sure the bulbs are new. If the bulbs are not the problem, there could be an issue with the fuse.
ECU defekt.