Referee Clancy lands Six Nations debut at Stade de France
Clancy, who was promoted to the International Rugby Board (IRB) high performance panel in November, becomes the third Irish referee to hit the top rankings.
Alain Rolland, now regarded as the top referee in the world, will take charge of two Six Nations games, as will South Africans Mark Lawrence and Jonathan Kaplan and Welsh official Nigel Owens.