The French Tennis Federation (FFT) and a police source said the player had been arrested, but did not offer more, according to Reuters.
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A source with direct knowledge of the matter, however, told Reuters the arrest was related to match-fixing allegations.
Earlier, Sizikova teamednup with Ekaterina Alexandrova in their convincing 6-1, 6-1 double's loss to Australian pair Ajila Tomljanovic and Storm Sanders.
The arrest comes after months of investigations into a 2020 French Open match.
Last September, French prosecutors opened an investigation into alleged match fixing in a women's doubles match at the French Open.
The investigation into "fraud in an organised group" and "active and passive corruption" was related to a doubles match between Romanian pair Andreea Mitu and Patricia Mari and Sizikova and American Madison Brengle.
Sizikova lost the match 7-6(8), 6-4.
Match fixing allegations investigated
German newspaper Die Welt and French sports daily L'Equipe said at the time there were suspicious betting patterns in the first round of a women's doubles match on September 30.
On that day, Sizikova was broken to love serving in game five of the second set, during which she double faulted twice.
It was reported that tens of thousands of euros were bet with several operators in different countries on the Romanian players winning this game.
Shamil Tarpischev, president of the Russian Tennis Federation, told the RIA news agency that he had been informed of Sizikova's detention. TASS news agency also reported that the Russian embassy in Paris had been informed of the situation.
"We have not received any documents (regarding the case), so it's difficult to make an assessment of what has happened," Tarpischev was quoted as saying.
The Russian Tennis Federation did not immediately respond to a request for comment.
The International Tennis Integrity Agency, which deals with corruption in the sport, said it would not comment.
The ITIA is an independent body set up by the tennis governing bodies.
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