customers are tasting natto. although french people are familiar with japanese food, they don't very often come across natto. >> translator: it is sticky, but it looks like it's good for your health. i'll buy some. >> reporter: the supermarket didn't import it from japan, a frenchman made it in france. a package cost about $5. sales have doubled over the past year, as more french people demand healthier food. he lives in the province region of southern france. it's here that he makes natto. he set up a small factory at his home. he makes natto by hand. the only soybeans he uses are organically grown. he discovered natto 40 years ago when he taught french in tokyo. at first he was taken aback by the sight and smell, but gradually, the unique taste won him over. he started eating the food every day. 17 years ago, he returned to japan because he wanted to learn how to make his own natto. he chose the prefecture where most natto is made. >> translator: it was really complicated. it took me a lot of time. actually, to