PARIS — French taxi companies and Uber are still as much at each other's throats as they were back in mid-2015 during violent protests that shocked the country — with more clashes reported Tuesday.

But the two competing interests have since discovered that they have something in common: Both are alarmed by the rise of Heetch, a French ride-sharing app launched in 2013. Both accuse the new service of unfair competition.

Heetch is based on a model similar to that of Uber. It connects clients with non-professional drivers using their own cars, but with a little twist: It only operates between 8 p.m. and 6 a.m., and at the end of the ride there is a suggested price that users are free to augment. Heetch was targeted by a national decree that banned Uber's app UberPOP. But the company has refused to be painted with the same brush, continuing its business despite the arrests of some of its hobbyist drivers. And it has built itself a growing customer base that has taxis and other driving services equally worried.

"Heetch continues to provide illegal transportation disguised as a car-sharing service, despite the decision of the Constitutional Council," a joint statement of taxi drivers released Jan. 7 said. They believe the company is illegally cutting into their business, along with similar services such as Chauffeur-privé. Right now Heetch is the second most-downloaded transportation app on Apple's App Store, behind Uber.

These companies are clearly worried about the prospect of losing revenue during the night, when Heetch is operational. But it goes deeper than. Some private drivers for Uber and others services — and many traditional taxi drivers too — are double-dipping, operating on the Heetch platform as well, an Uber France spokesman claims. That means diluting the availability of cars available for Uber and taxi clients.

Co-founder and CEO Teddy Pellerin keeps a low profile. "Our activity isn't exploding as much as some people want to believe," he says. Heetch now claims 50,000 rides a week*, compared to 40,000 in June 2015. But the app is now beginning to expand abroad, launching in Warsaw in mid-December. And at least one other European capital is expected to follow in the first quarter of this year.

Pellerin also maintains that Heetch is legal, because it doesn't provide a transportation service for a precise fee, he says. The price is only suggested. "Passengers are totally free to pay whatever they want at the end of the ride," he says. "And our drivers' income is limited to 6,000 euros ($6,500) per year, which is the average annual cost for their cars." In 2015, their average income was 1,850 euros ($2,000).

The argument doesn't convince Yves Weisselberger, founder of SnapCar. "Heetch does the same job as us, except their costs are twice as low because they don't pay any taxes," he says. "I don't want this app to be shut down, but the government needs to clearly say at some point what's allowed and what isn't."

*Correction: An earlier version of the story incorrectly stated the number of rides Heetch reports. It is 50,000 rides per week, not per day. Sorry.