Alleged financial crimes, but nothing that sounds super serious (like major fraud on investors would be) - more like hiding assets, underreporting income and misusing company assets for personal use. I haven’t seen any numbers, though.
His Wiki page has a pretty good summary of the charges - (other than that - he is a pretty impressive character on a whole lot of levels - Speaks 4 1/2 languages and is a citizen of Brazil, France and Lebanon)
https://en.wikipedia.org/wiki/Carlos_Ghosn
how does one speak 1/2 of a language?