4 Fishing Siblings French 1900s Poisson d'Avril Fish Postcards

4 French postcards from the early 1900s celebrating the
1st April with pairs of siblings and FISH

In France, April 1st is celebrated  as Poisson d'Avril (April Fish) the French equivalent of
April Fools' Day when people play jokes on eachother, usually with a fishy theme.

Why fish remains unclear, but it might have started in 1564, when King Charles IX
moved the start of the French New Year from April 1st to January 1st.
People who stubbornly kept celebrating the new year at the beginning of April
were mocked with odd gifts, ..often involving fish...because, maybe,
the 1st April falls during Lent when eating fish was restricted.
Who knows !
Please have a look at all 5 photos for close ups.