The International Worker’s Day on May Day (1 May) celebrates labourers and working class all over the world. In France, this public holiday is called la Fête du travail. The tradition here is to offer lily of the valley but also to march friendly with trade unions in the name of all those who fought for employee rights. 
French people are delighted when 1 May is on Thursday or Monday because they can take a long weekend! In french, we call this “faire le pont“, a metaphor meaning you have the opportunity to use a bridge and… cross over your work 😀
“Bonne fête du travail” ?
Question is: do people in France celebrate this day by whishing “bonne fête du travail” or “bonne fête du 1er mai” to each other? The answer is… no. For the majority of them, it is an apportunity to spend more time with their family or friends, travel or practise their hobby.
But you know what? If you do so, they may stare at you but since you are a foreigner, they won’t take offence (in french “en faire tout un fromage“!).