Here are some visualizations of important French vital statistics (marriages, births and divorces). I've chosen these three because we can clearly see the impact of the war on French society.

Marriages

Source: Michel Huber, La population de la France pendant la guerre (1931), page 223, citing Statistique du mouvement de la population, 1914-1919. The data is for only 77 departments of the 87 in France as 10 departments were occupied by Germany during the war.

Divorces

Source: Michel Huber, La population de la France pendant la guerre (1931), page 248

Live Births

Source: Michel Huber, La population de la France pendant la guerre (1931), page 238