The kick comes at the end — World's hottest chili flavours French chocolates

It is hard to come up with something new at Paris' annual chocolate fair, but French chocolatier Damien Vidal found a way to put a mouth-tingling twist on his confectionary: Incorporating the world's hottest chili.

Besides traditional ingredients such as raspberry, cassis and passion fruit, his marble-shaped "Bille en tete" (a play on a French idiom for "headfirst") chocolates are flavoured with Carolina Reaper, the world's hottest chili pepper according to Guinness World Records.

He managed to put just enough chili in them to give them a kick, but not too much so as to make them unpalatable.

Two Japanese tourists and other visitors at the chocolate fair gamely tried the shiny chocolate-chili balls and nobody spat them out.

"Mmm, it is both sweetie and spicy, not too spicy, the spicy taste is mild," said Japanese student Hitomi Ebitani.

French fair visitor Justine Bonneau agreed.

"It's really nice, it's a good surprise, the heat comes at the end. First it's fine, then it heats up and it gets hot," she said, making fun of her companion who she said was looking flushed after eating one.

Vidal - an award-winning pastry chef who has worked in top Parisian restaurants and was invited as "young talent" at the Paris Chocolate fair - said this delayed effect was exactly what he was looking for: sweet and gentle at first, then a taste explosion, which eases off after a few minutes.

"We've had to go through several recipes, several attempts to find the right balance, one that allows to please most people," he said.

French households on average eat 13.2 kilogrammes of chocolate per year, but leave enough for France to export more than 245,000 tonnes of chocolate, worth nearly one billion euros, each year, Paris chocolate industry data show.

• Europe