To the directors and celebrities who came to him for money to fund their projects, Frédéric Levesque was clever, charming, intelligent and the man who never said non.

He took their calls at any time of the day or night, calmed them and proposed solutions to their financial woes; on occasions he did not even ask them to sign documents on the loans he made for hundreds of thousands of euros, they told French investigators..

When he changed banks, his clients and their money went with him. He told friends – who told the French edition of Vanity Fair – that he was on first-name terms with his idol, the Australian singer Kylie Minogue, then partner to the French actor Olivier Martinez, one of his clients. Minogue, he recounted, had sent him a gift: a Rolex Datejust watch hidden in a box of biscuits made by her mother.

What the beneficiaries of Levesque’s largesse did not know, however, was that the money he came up with was allegedly not his to lend.

According to prosecutors, the 49-year-old banker took an estimated €2m out of wealthy clients’ accounts to lend to not-so-rich but famous friends, and borrowed millions more from others.

On Monday, Levesque went on trial accused of “abuse of confidence”, fraud and falsifying documents after a French actor reported him to investigators, who accused him of cheating clients out of up to €5m.

Investigators do not accuse him of personally profiting financially from his activities, but say Levesque was fascinated by the world of celebrities and wanted to be part of it. Among actors who reportedly trusted him with their secrets and their money were Juliette Binoche, Monica Bellucci and Isabelle Adjani, who told investigators she found the banker “very competent … and very kind”.

The court will hear Levesque’s alleged juggling of clients’ money began in 2003 when he was approached by a well-known French film director who needed a large sum of money to complete his new movie. Unknown to the director, Levesque allegedly took the money from the account of one of his wealthy foreign clients who had an untouched €2m in the bank and who, he believed, would not notice it was missing if it was reimbursed quickly.

It was reportedly paid back with interest and nobody was apparently the wiser. Levesque told the police he even paid the interest to the client from whose account the money had been taken but said the problems began when one of his showbiz friends failed to pay back a loan within the agreed time.

It was at this point, prosecutors say, Levesque found himself in a vicious circle of taking money from accounts to cover the missing funds in others. To do so, they allege, he convinced other celebrated clients to invest in non-existent projects and investments, or forged their signatures on documents. Much of the borrowed money has since been paid back, but others told investigators they are still owed substantial sums.

Among his victims, the actor Mylène Demongeot allegedly gave him €1.6m to invest in an imaginary project in Brazil. She told the police briade investigating Levesque that he was “very clever, charming and intelligent”. The director Alexandre Arcady, who when questioned by police described the banker as “always ready to help” and the actor Samy Naceri, who starred in Taxi, are also listed as victims who lost money.

Alerted by the numerous bank transfers made in his name, Tracfin, the French economy ministry’s anti-money-laundering unit, was ready to bring Levesque in for questioning when he reportedly sent them a long email asking to be seen “as soon as possible”. Five days later he was under arrest.

In an article in the French edition of Vanity Fair, friends said the teenage Levesque, an only child, had adored the musical Les Misérables and had dreamed of becoming a singer and dancer. Aged 27, he moved to Los Angeles for Arista Records, which produced Whitney Houston and Carlos Santana. “It was one of the best times of my life,” he told friends.

He returned to France two years later after his mother was diagnosed with terminal cancer. After her death, he joined the branch of a leading French bank that specialised in clients from cinema and television.

A psychiatrist who analysed Levesque as part of the investigation carried out by a juge d’instruction, told police the accused “wanted to please and to be liked”. She said he was looking to “feed his ego and the feeling of his own importance”.

Contacted by Le Parisien newspaper, Levesque’s lawyer did not want to comment before the trial.

The trial continues until September 25.