Groupama underwriting and pricing director Maggie Litster is to leave the insurer at the end of November for a career break.
Groupama said the gap year had been planned for some time and said it was supportive of the change.
Pierre Lefèvre, Groupama chairman and chief executive, said: "We will be very sad to lose Maggie. She has been an integral part of our Group and a major influence in determining our future direction.
"However, we understand that she feels that now would be a good time to take a break from the industry - although she has not ruled out the possibility of coming back at some time in the future."
Groupama said it would consider its options before replacing Litster. In the interim managing director François-Xavier Boisseau is to assume personal responsibility for the group's underwriting, pricing and operations activities, as well as for various line reports.