At current when working with the french culture, the year in the date will default be represented with 2Y (dd/MM/yy)
This potentially creates a problem for dates>2030, a date like 01/01/30 would be save as 1930 instead of 2030.
When looking at other culture such nl-BE, en-GB, 4 digits are always used for the year.
I propose to change this also for the french culture so that dd/MM/yyyy would become the standard format.
PS: You can download the culture file and change it, but you'd experience a problem with the popup editor in combination with a display template... in this case the local culture file will be ignored and 2 digits would still be used for the date