To Mr. Lhéritier, this is proof that Aristophil was no Ponzi scheme, because only a lunatic would sink money into a doomed venture. Not so, say critics. If Mr. Lhéritier hadn’t infused his company with cash, Aristophil would have collapsed and he would have instantly gone from eminence to pariah.

Regardless, winning the lottery wasn’t enough. Far more cash was needed to cover the hundreds of millions of dollars that aging investors had begun to demand.

“By 2014, these people wanted to sell their assets,” said Philippe Julien, an attorney with PDGB, a law firm leading one of several class-action suits on behalf of investors. “Aristophil was unable to say yes. The company didn’t say no, either. It just was unable to pay, or it would pay a little and say it would pay more in a few years.”

Mr. Lhéritier scrambled. Through an intermediary, he tried to sell his Einstein documents to a list of notables, including the Aga Khan, Harvey Weinstein and Steven Spielberg, for $32 million. “They all require second opinions,” the intermediary wrote to Mr. Lhéritier. The potential buyers passed.

Prodded by angry investors, the French authorities shut down Aristophil on a Tuesday morning in November 2014. Mr. Lhéritier’s home was searched, too.

A criminal investigation is underway to determine whether Mr. Lhéritier’s indictment will continue into prosecution, and if there is a trial the proceedings could stretch on for years. In the meantime, he spends most days at home, in search of proof that well-placed civil servants targeted him for destruction.

At present, Mr. Lhéritier has more hunches than hard evidence. He says he angered influential players in the investment world, and regulators in their thrall, because Aristophil was a disrupter. He also says he embarrassed government officials by giving them color photocopies of letters by de Gaulle after they demanded the originals displayed in his museum.