Schools in France are now required to display the French and EU flags in classrooms alongside the words to the national anthem, reports the BBC.
The move - effective from the start of the school year on Monday - was approved as part of educational reforms passed by parliament in February.
It was suggested by a centre-right opposition MP but endorsed by President Emmanuel Macron's centrist government.
The new rule has been controversial. Critics say it is overly nationalistic.
All classrooms in primary and secondary schools must now display the national flag, words to the Marseillaise, and the national motto - "Liberté, Égalité, Fraternité".
The main changes include compulsory education from the age of three, instead of six as had been the case in France since the 19th Century.