I do not know the exact answer to your question.
During the week of Easter, there usually are many
French tourists visiting their families in the countryside.
Food shops will always be open in the mornings, and
it will just depend on the particular day.

I am sure there will be plenty of families strolling
through Collanges La Rouge after Easter lunch, but
I am not sure if the shops, other than a place for
an afternoon coffee will be open.

Spring is in the air, and whether or not the shops
are open for Good Friday or Easter Sunday or Monday,
this is a lovely spot just for a stroll.

Are all shops open in Collanges la Rouge in the time of 21-03 untill 31-03?

greetings, Mme de Groot