Turning Paris's underground car parks into mushrooms farms

What do you do with an old car park that no-one wants to park in? Why not use them to grow mushrooms - or even salad?

Paris built too many underground car parks in the 1960s and 70s. Falling car ownership means many are standing empty, or finding new and surprising uses.

Produced, filmed and edited by digital reporter Dougal Shaw in La Chapelle, north Paris.