The suspect in the Brussels Jewish museum shooting attack bragged that he was planning a terror attack in Paris, French media reported Monday, but French authorities said there was evidence the attack was imminent.

On Saturday, French magazine Le Point quoted its journalist Nicolas Henin as saying that Mehdi Nemmouche was one of this captors in Syria, where he was held for for nearly a year by extremists along with slain U.S. journalists James Foley and Steven Sotloff.

Following that report, the newspaper Liberation said on Monday that Nemmouche bragged about planning an attack "five times worse" than the 2012 Toulouse shootings perpetrated by Mohamed Merah, in which seven people died. Nemmouche allegedly said the attack would take place on Bastille Day on July 14.

The Paris prosecutor's office, which is investigating Nemmouche, said Monday however that they have seen no evidence of "plans for an attack on French soil, especially not on July 14 in Paris," according to a report in The Local.

According to Liberation, Nemmouche is said to have spoken of the plans to four French journalists held in Syria, who were released in April. After their release, the four gave statements to French authorities, who are investigating him on suspicion of the May attack.

In remarks carried on the website of Le Point magazine, Henin said Nemmouche was part of a small group of French-speaking Islamic State recruits that regularly tortured a group of Syrian prisoners held alongside Western journalists in Aleppo.

French Interior Minister Bernard Cazeneuve said that French intelligence services "transferred elements to the judiciary that suggest (Nemmouche) may have been the jailer of our hostages," after a report in the newspaper Le Monde, The Local reported.

According to a police source, the four journalists recognized Nemmouche from photographs taken after he was arrested.

According to Le Point, Henin did not speak out about Nemmouche being his captor in Syria earlier out of concern for the safety of other hostages still being held there, but following the Le Monde report he decided to go public.

Didier Francoise from Europe 1, one of the other French journalists released in April, said the Le Monde report was "irresponsible," and that it could pose problems for the investigation against Nemmouche and for the hostages still being held in Syria.

Four people, including two Israelis, died in the Brussels attack on May 24. Nemmouche, a Frenchman, was remanded in custody in August on suspicion of "murder in a terrorist context," The Local said.

In Le Point, Henin said Nemmouche was "a self-centred fantasist for whom jihad was finally an excuse to satisfy his morbid thirst for notoriety. A young man lost and perverse," according to the report. At a later press conference, he said, "He probably didn't join the Syria fight for some ideal, but above all due to a lack of recognition."