The RnB artist has found herself embroiled in political controversy since it was reported that French president Emanuel Macron proposed the possibility of the superstar singer of "Djadja” performing at the Paris Games opening ceremony in the River Seine.

The six were detained on Tuesday after being "identified in the course of an investigation over incitement to hatred online", a source in the state prosecution service, who asked not to be named, told AFP. They were released the following day, the source said, adding that investigators had also examined material seized during searches.

Nakamura, 29, was at the centre of a political storm after Macron suggested she could perform at the 26 July Olympic event. Far-right politicians and conservatives rounded on the RnB artist, accusing her of "vulgarity" and not respecting the French language. Police opened a probe after the anti-racism group LICRA in March flagged numerous racist online messages targeting Nakamura.

"She is one of the great French artists, one of those who are most acclaimed around the world. But she won't be the only one, far from it," Macron said back in April, while condemning the comments about the singer, "The reactions have shocked me. There have been some really racist reactions."

A survey conducted then by Elabe for BFMTV shed light on public sentiment regarding her potential participation in the proceedings. The findings revealed that nearly half of French respondents, constituting 49 per cent, expressed reservations about the singer's involvement, deeming it a "bad idea." In contrast, a minority, comprising 21 per cent of respondents, viewed the idea positively, considering it a "good idea."

The performers for the opening ceremony remain a tightly guarded secret. It seems almost certain that Nakamura will take part, not least because rumours of her performing triggered the racist backlash earlier in the year that has added to pressure on the organisers to include her. 

One French newspaper, the Canard Enchaine, said Celine Dion may be involved, though she has suffered severe health issues in recent years that could prevent her from appearing. It is said only around 10 people know exactly how the entire show will unfurl.

It is the first time an Olympics opening ceremony will be held outside a stadium, taking over six kilometres (3.7 miles) of the River Seine with some 3,000 dancers, musicians, actors and circus performers performing along the banks and bridges with an estimated 326,000 spectators. Thousands of athletes, out of a total of 10,500 competitors, will sail down the river on 85 boats. It is hoped more than a billion viewers will follow the broadcast around the world.

Recently, superstar DJ David Guetta expressed his shock over not receiving a call and seemed upset when asked by Agence France-Presse why he was not performing on 26 July. "If you have the answer, please tell me, because I don't understand at all," he said before a gig at the Chateau de Chambord in the Loire Valley.

The soundtrack is expected to combine "French Touch" electro, pop, symphony orchestra and choirs, overseen by musical director Victor Le Masne. Thomas Jolly, artistic director for the Paris Games, said it would be wide-ranging and that French music was as much opera singer Natalie Dessay as rapper Jul and icon Edith Piaf.