Licorne was the fourth   thermonuclear test and the fifth  largest conducted by France. The device was suspended  from a balloon 500 meters above the Dindon testing sector. The mushroom cloud reached an  altitude of 24,000 meters approximately six minutes after shot time, with the base of the  cloud reaching 15,800 meters.  Licorne nuclear test in 1970.   
 
Atomic Weapons are a hobby of mine.  Gorgeous shot. 
 
 
 http://www.youtube.com/watch?v=s8yvZ7pIZns