Saint Patrick’s Day is celebrated on the 17th of March.
It is a national holiday in Ireland
Patrick was a Roman who lived in Britain in the 4th century. He became the first Christian missionnary in Ireland.
An Irish tale tells how Patrick used the three-leafed shamrock to explain the Trinity . 
Saint Patrick ‘s flag 
represents Saint Patrick , the patron saint of Ireland.
It is also said to represent a neutral flag of Ireland.
In Dublin the festival lasts a week !
http://www.st-patricks-day.com/
Saint Patrick’s Day is also celebrated in many countries around the world.
Here’s an example in Chicago,USA
In Marseilles too !
