French president Emmanuel Macron’s chief of staff Alexis Kohler is under formal investigation for his alleged links with Mediterranean Shipping Co (MSC).

The indictment by the national financial crimes prosecutor comes four years after the first reports emerged of a probe into Kohler, who has family ties to the giant Swiss container ship and cruise ship owner’s founder Gianluigi Aponte.

The prosecutor’s office said in a statement that Kohler, currently the secretary-general of the French presidency, “has been put under formal investigation for unlawful taking of interest.”

A formal investigation in French law means there is evidence implicating a suspect, but does not mean a charge has been laid.

Kohler is Macron’s closest and most influential adviser.

The president’s office has not responded but Le Figaro newspaper said the president will retain Kohler during the probe.

“Alexis Kohler strongly challenges having committed any crime. The subsequent procedure, to which he now has access, will enable him to prove his innocence,” Kohler’s lawyer Eric Dezeuze told Reuters.

Macron’s office has previously said Kohler had at no time hidden his family ties to the Aponte family.

His mother is reportedly a cousin of Aponte’s wife Rafaela.

The formal investigation comes after anti-corruption group Anticor filed a complaint accusing Kohler of breaking conflict-of-interest rules.

Government jobs and MSC position

Kohler worked for MSC in between two government jobs.

The complaint alleged a conflict of interest based on Kohler’s dealings with MSC while he was working for the French state holdings agency between 2012 and 2014 and later as a senior official in Macron’s team at the finance ministry from 2014 to 2016.

Kohler moved to Geneva to sit on MSC’s board in 2016.

He stepped down nine months later when Macron became president in 2017.

In 2018, the French prosecutor said it had opened an initial probe following media reports that alleged Kohler, while employed by the previous government, had worked on files of interest to MSC, where he became chief financial officer of MSC Cruises in 2016.

There is no suggestion of wrongdoing by MSC, which has been contacted for comment.

Kohler had been economy minister in Francois Hollande’s government, as well as involved with France’s investment arm, the Agence des Participations de l’Etat.

Macron’s office said at that time the allegations were based on news stories containing “several serious factual mistakes”.

It added that Kohler “systematically stayed away from any decision linked to this company”.