GENEVA (AFP) - The French have been credited with inventing the bidet and popularising pissoirs or public urinals, and now they can add the biodegradable and portable toilet to their name. Frenchman Mayer Helewa designed the lightweight, easy to construct and carry toilet after Hurricane Katrina, when thousands of displaced people were crammed into a stadium for a week, with hardly any access to facilities. Its a taboo subjet, but necessary in case of natural disasters, he told AFP at the annual International Exhibition of Inventions in Geneva, pointing to the earthquakes in Japan and Haiti that displaced tens of thousands of people. The first problem is to have access to a toilet. Because if not, people will do their business wherever, and you end up with epidemics such as cholera, said Helewa, who is a doctor.