The police union says that he was depressed, but it seems odd for someone who was exhibiting signs of depression to have such an important job. He took the position over from someone who also committed suicide only a year or so ago.
Maybe he felt responsible for the lack of police firepower around the cartoonists, who were known jihadi targets.
He lived and worked in Limoges. Limoges is a four hour drive from Paris. Why would he feel responsible? The only info about this suicide is on conspiracy sites, and posts on these sites have him as the chief investigator in the Paris shootings. NOT true at all! Typical of conspiracy sites.