Where is the fuel filter on a mk3 punto?

Also when changing it ive read you have to de-pressurise the fuel system, is this right?

Yes...unless you want fuel coming out under high pressure as soon as you take the filter off...not a nice thing as it'd probably smeg ya right up should it pieerce your skin and get into your blood stream.
Not sure where it is on a mk3 though

There isn't one.

No filter for Petrol exactly like DanGil says, diesel is in the engine bay.

Actually before someone corrects me, there is a filter built into the pump for petrols but this is not a seviceable part.

There isnt as I tried to get one the other day and get my mate whos a mechanic so he can service my car and that was one filter the punto didnt have.