How do I bypass my catalitique converter on a Peugeot 307?

I have a Peugeot 307, but the previous owner took out the Catalitique Converter (for some stupid reason) and now my car is picking up that it's missing. I have reset my computer box, but after a week, it went back to picking up the fault... I know there is a way that you can insert something so that it picks up that there is a Catalitique Converter present, but I'm not sure how it all works?|||ilegal to by pass you have to buy a new one|||it is unlawful to remove your cat, if you are stop by the police there are hefty fine for not having them on your car, not to mention you transport certificate.go and get another fitted and the problem is solved.|||it,s illegal but you can take it off and put a test pipe where the cat. was.|||put in a catalytic converter. Your emissions effect everybody.