How many working days in year 2124?
Here is the detail of the calculation:
Because 2124 is a leap year, it has 366 days.
Let's remove 53 saturdays and 53 sundays. It remains 260 days.
Now, let's remove 8 public holidays that do not fall during a weekend and we obtain 252 working days in 2124.
 Here is the list of these 8 public holidays: 
 
 1. Lundi de Pâques : понедельник, 3 апрель, 2124 
2. Fête du Travail : понедельник, 1 май, 2124 
3. Jeudi de l'Ascension : четверг, 11 май, 2124 
4. Lundi de la Pentecôte : понедельник, 22 май, 2124 
5. Fête Nationale : пятница, 21 июль, 2124 
6. Assomption : вторник, 15 август, 2124 
7. Toussaint : среда, 1 ноябрь, 2124 
8. Noël : понедельник, 25 декабрь, 2124 
And here are the 2 public holidays falling on a weekend:
1. Jour de l'An : суббота, 1 январь, 2124 
2. Fête de l'Armistice : суббота, 11 ноябрь, 2124