fuel warning light stays on after filling up ? Peugeot 307 hdi any help ?

It could just be the fuse for that light is not functioning properly.

It is knackered.

is you gas cap bad l would check that first. did you forget to close it at one point and the light came on? the only other problem l could see is the fuel pump floater arm is broken and not floating up when there is fuel in the tank. that right there alone might be a big fix

similar problem- earth wire had broke.

the fuel light is connected to the float in the tank , it is probably bad you should go top a service center. the only other thing that might affect the light is a short in the dash panel.

307s are prone to electrical malfunctions.. it may be a full tank and read empty ..but be prepared for many other faults like this.

in tank sender unit or short to earth 99% sender req replacement

If the gauge is working ok and you can live with the light on then leave well alone, or fit a new sender unit to tank.