I have read some reports/reviews here and thought it would be really lovely to stay right on the Mont for 1 night, but have found hotels booked already for mid-Sept 2016. Has anyone here experienced this?

maybe prices for next year have not been added. This occurs in the likes of booking.com Trip Advisor etc.
Contact the hotel directly.

You are too early to use online booking for the reason mentioned above. If you have to book now, you have to do it manually presuming they have started accepting reservations.

I emailed a couple of MSM hotels because their websites said "no availability" for May 2016 and the response was that those dates wouldn't be available for booking until mid-November. They didn't say you could call ahead, but I can wait until November.

I wish their websites would just say it's too early instead of "no availability".

A lot of hotels won't book that far in advance. I think by manual, greg mean you'll have to call them up, or email at least.

Oh, thank you for your responses! Here I was freaking out. My husbands family plans things way in advance, and I tend to procrastinate, but I didn't think 11 months in advance was leaving things too late!

I am in the beginning stages of planning a north to south France trip next September. Brittany, Normandy, Paris then Provence.

Having fun looking at all the options, and am loving this site for all of your great and varied advice.