When to come?

The cairn of petit Mont is open in 2021:

June, till july the 4th and and septembre 
every days of the week (except on Mondays) from 2PM to 6:30 PM

From , July 5th to August 31th (summer break)
every days of the week from 10 AM to 7PM

Winter and All Saints Holidays
every days of the week (except on Mondays) from 2PM to 5:30 PM