On Monday nights in Brooklyn, a band of Frenchmen and Americans play Peruvian music.

“I know that sounds a bit absurd,” said Olivier Conan, lead singer of the band, Chicha Libre, whose name is a tribute to the craze for a style of music called Chicha that took root in the Peruvian Amazon in the early 1970s.

“But we take the music very seriously, and we do it justice,” said Mr. Conan, 46, as he sat last Monday with a drink and several band members at a table outside Barbès, a bistro in Park Slope. Later, people flocked to the bistro to hear him play the cuatro, a South American guitar he uses to strum the perky blend of Latin rhythms, surf music and psychedelic pop he first heard three years ago while vacationing in Lima, Peru.

“All the street vendors were playing Chicha on their boomboxes,” said Mr. Conan, fiddling with his cuatro as the sun began to sink behind rows of neatly lined brownstones. “I just fell in love with it.”

Mr. Conan was then in a French band named Bébé Eiffel, and he was determined to change its cultural and ethnic tunes after returning from Peru. He sat down with Vincent Douglas, a longtime friend and member of the band — Mr. Douglas and Mr. Conan own Barbès — to discuss the possibility of putting a Spanish accent on a new act.

Mr. Douglas, an electric guitarist, said he was “immediately blown away” by the recordings that Mr. Conan had brought back from South America.

“Olivier had me listen to this music, and it was just incredible,” said Mr. Douglas, 41, who has been a friend of Mr. Conan’s since they were teenagers growing up in Paris. “It had a real Latin vibe. It was very groove- and dance-oriented, and at the same time it was very rockish and surfy. I told him we should definitely start playing it.”

Chicha, which fuses traditional music from various parts of Peru with musical styles from Colombia and Venezuela, was played and danced to mostly in Lima’s poor suburbs by people who had migrated from the Amazon and the Andes in search of a better way of life.

Mr. Conan said that the band recently released a CD called “Sonido Amazonico” (Sound of the Amazon) and would perform at the Montreal International Jazz Festival on Wednesday.

Dressed in a cowboy hat and a dark blazer he described as “vintage Salvation Army,” he said he “could not imagine anyone else in New York, or anywhere in America, playing Chicha music.”

“If we weren’t playing it here,” he claimed, “you couldn’t hear it anywhere.”

Mr. Conan then got up and opened a cellar door to fetch the instruments, amplifiers and other equipment that belong to the six-man band. The other members are Nicholas Cudahy (bass), Greg Burrows and Timothy Quigley (percussion), and Joshua Camp, who plays an Electrovox, which Mr. Olivier described as an instrument that looks like an accordion but functions as an organ.

“We start our show at 9:30, and we get more artsy types than stockbrokers in here, people from their 20s to their 40s,” Mr. Conan said. “Of course, we get a lot of Peruvians from all around the city, but not many middle- or upper-class Peruvians because Chicha is mostly associated with the ghetto slums of Lima, so some people look down upon it.”

About an hour after sunset, Chicha Libre’s first set was under way. A dozen chairs in the bistro’s back room were quickly filled, and the band began by playing a number laced with enough spaghetti western strains to create the feeling that Charles Bronson, six-gun in hand, was about to walk into the room.

“They are an amazing band,” said Morgan Stoffregen, 29, who makes the short trip from Flatbush to the bistro, at Ninth Street and Sixth Avenue, every Monday to hear Chicha Libre play.

Ms. Stoffregen fell in love with Chicha music during a recent trip to Oaxaca, Mexico, where she happened to hear it played in a bar.

“One night I was home about 8:30, searching the Internet for a place where I could hear Chicha,” Ms. Stoffregen said. “I came across these guys, and about an hour later that same night, I was sitting here, listening to them perform.”

Elise Marafioti, a 27-year-old waitress, was busy running drinks to the dimly lighted tables and to a few dozen people dancing along the walls. “Monday nights can get kind of crazy in here,” she said. “Especially when the place gets packed and the floors start shaking.”

By Chicha Libre’s second set, the tiny room was indeed packed, and the floors were shaking, a tribute to a Latin band with nary an ounce of Latin blood coursing through their musical veins.

“Hey, if six Latinos want to start up a French band, I think that would be a great thing,” Mr. Douglas said. “I don’t think music belongs to anyone; in fact, it belongs to everyone.”