Beche and Thiriet ended up winning the six-hour race in their ORECA-Nissan 03 by more than a lap after the challenge from the Greaves Zytek wilted in the fifth hour.
Greaves driver Alex Brundle dislodged part of the front bodywork after taking over the Zytek-Nissan Z11SN and a pitlane infraction at the resulting stop resulted in a two-minute stop-go penalty. That left the car, which was started by Tom Kimber-Smith, in fourth place at the chequered flag.
The race for overall victory had initially been a three-way fight between the TDS ORECA, the Greaves Zytek and the Status GP team's brand-new Lola-Judd/BMW B12/80 driven by Yelmer Buurman, Alexander Sims and Dean Stirling.
The Status car fell out of contention when SPEED EuroSeries graduate Stirling, racing a modern LMP2 for the first time, was unable to match the times of his team-mates after taking over from Buurman in the third hour.
The Sebastien Loeb Racing ORECA-Nissan 03 driven by Nicolas Minassain, Nicolas Marroc and Stephane Sarrazin came through to finish a lap down on the winners. The car, which was only finished in the week of the race, was never in contention for the victory.
Sims brought the Status Lola back to third after the Greaves car's problems, finishing 30s down on Sarrazin at the finish.
The JMW Motorsport Ferrari squad sealed a dramatic victory in the GTE Pro class. James Walker and Jonny Cocker completed the race on four stops in their 458 Italia, whereas the JMB Ferrari that had led most of the way in the hands of Jamie Melo and Marco Frezza needed a late-race splash-and-dash.
Cocker sneaked ahead as Melo exited the pits with 11 minutes to go and was able to hold on to claim a one-second victory.
GTE Am honours went to the ProSpeed Porsche 911 GT3-RSR of Marc Goossens and Maxime Soulet.
Curtis Racing Technologies drivers Phil Keen, John Hartshorne and Alex Kapadia came out on top in the one-make LMPC category.
Results - 189 laps:
1. P2 Thiriet/Beche TDS ORECA-Nissan 6h00m53.302s
2. P2 Sarrazin/Minassian/Marroc Loeb ORECA-Nissan + 1 lap
3. P2 Stirling/Sims/Buurman Status Lola-Judd + 1 lap
4. P2 Brundle/Kimber-Smith/Ordonez Greaves Zytek-Nissan + 1 lap
5. P2 Hirschi/Meichtry/Frey Race Performance ORECA-Judd + 3 laps
6. P2 Kraihamer/Moreau/Nicolet OAK Morgan-Judd + 4 laps
7. P2 Bruni/Perez Companc/Kaffer Pecom ORECA-Nissan + 6 laps
8. PC Kapadia/Keen/Hartshorne Curtis FLM + 12 laps
9. GTE P Walker/Cocker JMW Ferrari + 13 laps
10. GTE P Melo/Frezza JMB Ferrari + 13 laps
11. GTE A Goossens/Soulet Prospeed Porsche + 14 laps
12. P2 Thirion/Rosier Extreme Limite Norma-Judd + 14 laps
13. P2 Hancock/Dolan Jota Zytek-Nissan + 15 laps
14. GTE A Armindo/Narac/Pons Imsa Porsche + 15 laps
15. GTE P Peter/Broniszewski Kessel Ferrari + 15 laps
16. GTE A Ferte/Illiano JMB Ferrari + 17 laps
17. GTE A Goethe/Hall Gulf Aston Martin + 29 laps
18. GTE A Cioci/Griffin/Perazzini AF Corse Ferrari + 45 laps
PC Merlin/Vignali/Dagoneau Boutsen Ginion FLM 111 laps
P2 Moro/Firth/Hughes Murphy ORECA-Nissan 64 laps
P2 Buemi/Briere/Clarke Boutsen Ginion ORECA-Nissan 27 laps