Geoff McCabe and Michael Watt bagged doubles as Ireland made an impressive start in the 5 Nations tournament in Paris on Tuesday.
McCabe netted twice in the opeing six minutes to put the Irish in control and Michael Watt made it 3-0 on 32 minutes.
Andy McConnell added the fourth a minute later before Korea, ranked sixth in the world, pulled one back early in the second half.
Watt sealed a comfortable win with a fine finish after 55 minutes.
Ireland face a tougher test on Wednesday with Australia their opponents.