Ridly Scott’s historical movies always need to be taken with a grain of salt. I love Gladiator, but as a history lesson, no. Kingdom of Heaven was dire, both as a movie and as history. Alien (not a historical movie, obviously!) was very good. Prometheus less so, and annoyingly riddled with unnecessary scientific inaccuracies.
But I am looking forward to Napoleon. As long as there are no egregious attempts to preach, and no obvious anachronisms in attitudes, it will be possible to overlook any minor inaccuracies, and just enjoy it as a movie.