I don't care for UAs early arrivals-it cuts off the day of departure and gets you to Paris way too early. They used to have later arrivals before they eliminated most of their flights to CDG.

Not to concern you too much, but I would take note of the post above that mentioned keeping your valuables with you. Many of the Paris hotels will "keep an eye" on your stuff but that often amounts to having it in a public area near the front desk. With all the check-outs before noon, there's a lot of people roaming through those lobbies. Keep the stuff you leave locked and take the high-end camera with you.

Another activity for killing time until check-in is a bus tour sightseeing the sites in Paris. Those buses seem to be out early, and while it's a little dreamy on jet lag, it's also low stress, and maybe something you'd do anyway.

BTW, a 7 am landing leading to an 8 am arrival in town is optimal. I've done it but not often.