(Reuters) -French banking giant Societe Generale said on Friday it had appointed President Emmanuel Macron's chief of staff Alexis Kohler as executive vice president, effective June 2025.

Kohler, who has been Macron's chief of staff since the start of his first term in 2017, will be responsible for leading M&A, equity capital markets and acquisition finance activities, as well as assisting CEO Slawomir Krupa in implementing transformation programmes within the bank.

He will also join Societe Generale's executive committee.

Like Macron, Kohler attended the elite Ecole Nationale d'Administration (ENA) school. He was also head of Macron's office when Macron was economy minister under President Francois Hollande between 2014 and 2016.

Kohler is seen as Macron's closest and most influential adviser. He is seen as so integral to Macron's thinking that he became nicknamed by some "Macron's second brain".

The office of France's financial prosecutor in 2019 dropped a year-long investigation into Kohler after it found no evidence of wrongdoing in an investigation into conflict of interest.

The prosecutor had been investigating whether Kohler breached conflict of interest rules while working for the state given his personal ties with the Swiss-Italian Mediterranean Shipping Company. Kohler and the Elysee had denied any wrongdoing.

(Reporting by Dimitri Rhodes, Dominique Vidalon and Richard LoughEditing by Himani Sarkar, Peter Graff and David Evans)