For numbers issued prior to 1973 the French enrollment number (No. d'immatriculation)
is a 13-digit number which is assigned by a local French Social Security fund when
a person begins to work. Numbers issued after 1972 contain 15 numbers.
The pertinent numbers for SSA are:
1st digit-indicates the sex of the worker. A male worker is a 1 and a female worker
is a 2.
2nd and 3rd digits-show the year of birth.
4th and 5th digits-show the month of birth (01-12).