"The idea is to be able to offer 360-degree images of places that were inaccessible before," Google spokesperson Anne-Gabrielle Dauba-Pantanacce said in an interview.
The riders, wearing Google tee-shirts and white helmets, are visiting well-known sites such as the Chateau de Versailles, west of Paris, the Jardin du Luxembourg on the city's Left Bank or Les Halles, in the busy center of the French capital.
Google is to map Paris until Aug. 20, then head to the north of the country. In the fall, the tricycle goes south, said Dauba-Pantanacce.
The company plans to add new photos to their Street View option in all French cities with tourist areas that may be of interest to visitors.
Similar tricycles have already combed the streets of Britain and Italy in June and July, said Dauba-Pantanacce. Google plans to make 3-D maps of streets in other European countries, but the schedule has not yet been set, she said.
Spotted Friday at La Defense, the tricycle looked decidedly out of place at the modern high-rise business center on Paris' western edge.
A clunky white pole in the back holds an octagonal platform with eight cameras on the sides and one on top. Each minute, the cameras take bursts of high-definition photos to allow online users to get a virtual tour of the area.
"I rode two hours this morning," said 25-year-old Gregory Landais, who was taking a break after cruising through La Defense, France's touch of Manhattan. "For a site like this, it can take up to five hours."
To respect people's privacy, Google has installed software that recognizes license plates and people's faces and automatically blurs them, Dauba-Pantanacce said. Google will then choose the best photos among the thousands taken.
The blurring comes to meet privacy concerns.
Google recently acceded to German demands to erase the raw footage of faces, house numbers, license plates and individuals who have told authorities they do not want their information used in the service.
Greek officials rejected a bid to photograph the nation's streets until more privacy safeguards are provided. Residents of one English village formed a human chain to stop a camera van, and in Japan the company agreed to reshoot views taken by a camera high enough to peer over fences.
The photos of Paris and other major French cities to follow were expected to be available online by the end of the year.
One curious sightseer was 46-year-old Jose Mountinho of Portugal.
"I've already seen Google Maps but I had no idea how they did it," Mountinho said.