The visitors seemed to be galvanised by these let-offs and after 20 minutes, lock Daniel Mannion (Wicklow) scored the opening try of the match following a period of concerted Irish pressure in which the visitors tested the Languedoc defence by moving the ball wide and attacking both flanks.
Full-back Callum Boland (Buccaneers) converted with an excellent kick from wide out on the left.
Just before half-time good handling by the Combined Provinces backs saw right winger Chris Farrell (Clogher Valley) score an unconverted try in the right hand corner.
The visitors started the second half in confident mood and almost stretched their lead with a penalty following a good restart.
However, it was not long before the Combined Provinces added to their tally. Following some Languedoc indiscipline, which saw a Languedoc a player sin-binned, full-back Boland kicked a penalty into touch close to the hosts' try-line.
Team captain Alan O'Connor took a good lineout ball and from the resulting driving maul, openside flanker Conor Clancy (Stoneyhurst College) touched down.
Full-back Boland once again added the points with another outstanding conversion. This should have been the signal for the young Irish side to 'cut loose', but instead they seemed to take their foot off the pedal and allowed Languedoc to score a blindside try from a scum close to the visitors' line to close the gap to 19-5.
Head coach Greg Lynch introduced a number of changes at this stage and the Combined Provinces side once again threatened the hosts with some good attacking play.
But it was from one of these attacks that the hosts took advantage of a stray pass to intercept and run almost the length of the pitch to score under the posts, leaving the visitors as 19-12 winners.
The status of the match was reflected by the attendance of the IRFU President John Callaghan and his FFR counterpart Pierre Camou, as well as the FFR Vice President Jacues Laurens. Also in attendance was the mayor of Narbonne.
The Irish management will now select a squad of 26 players to travel to Treviso for the FIRA-AER European Championships (March 26 to April 4).
COMBINED PROVINCES UNDER-18 CLUBS Team & Replacements (v Languedoc Selection):
15. Callum Boland (Buccaneers)
14. Chris Farrell (Clogher Valley)
13. Thomas Daly (Carlow)
12. Grant Connon (Newcastle)
11. Joe Keane (UL Bohemians)
10. Jack Carthy (Buccaneers)
9. Jack Walsh (London Wasps)
1. Kiearn Ball (Wellington College)
2. Jonathan Murphy (Banbridge)
3. Jake Considine (Young Munster)
4. Alan O'Connor (Skerries) (capt)
5. Daniel Mannion (Wicklow)
6. Charles Gallagher (Banbridge)
7. Conor Clancy (Stoneyhurst)
8. Eoghan Masterson (Portlaoise)
16. Tom Margetson (Wellington College)
17. Chris Tonge (Skerries)
18. Darren O'Shea (Crosshaven)
19. Akhlaque Khan (Navan)
20. Kieran Marmion (Kirkham GS)
21. Cian McGovern (Crosshaven)
22. Tom Chellew (Northampton School)