Racing 92 moved to the top of Pool 3 after claiming a 33-3 victory over Northampton at Stade Yves-du-Manoir on Saturday.
The homeside were in control from start to finish and fly-half Dan Carter delivered a superb all-round display on his debut for his new club.
Despite scoring five tries, Racing were made to put in a solid defensive display in the second period, and kept Northampton at bay throughout the game.
A controversial TMO decision ruled out a Luther Burrell try on the stroke of half-time, which proved to be a damaging blow to Northampton's chances of turning the scoreline around.
Carter played 64 minutes, kicking three of his four attempts, as well as putting in a great defensive display, which earned him the Man of the Match award.
Racing were on the front foot from early in the game, but it took 13 minutes to see Henry Chavancy dive for the corner to score the game's first try, which Carter converted from the touchline to open his account for the French club.
The Parisians continued to press, and five minutes after the first try was scored, loosehead prop Eddy Ben Arous found himself filling in at scrum-half, and he broke round the side of a ruck to reach for the line and score the second.
JJ Hanrahan kicked Northampton's first points on the half hour mark as they looked for a way back in to the game. With Racing 92 enduring a period of sustained pressure, full-back Brice Dulin intercepted a pass deep in his own half and showed a clean pair of heels to Ben Foden and George North to score from 90 metres, and Carter converted his third kick of the game.
Moments before the half-time whistle, the officials ruled out what looked like a try for Northampton's Burrell after he powered through a number of tackles, but the TMO ruled that he didn't get the ball down before being hauled in to touch.
Four minutes in to the second half and Dulin secured the bonus point for Racing with his second try of the game, after tighthead prop Ben Tameifuna bullied his way through the Northampton defence before offloading.
Carter's fourth attempt at the posts got caught in the wind and smacked the upright, as the former All Black lost his perfect record.
Tom Stephenson's score looked to have handed Jim Mallinder's side a way back in to the game, but Stephen Myler's final pass to the inside centre was found to be forward.
After a period of resilient defending from Racing 92, Johan Goosen broke past the Northampton defence to change the momentum, before the ball was shipped to Juan Imhoff to touch down under the posts.
As the game petered out, Racing continued defending stoutly, and were deserved winners as they rise above Northampton in the Pool 3 standings.
For Racing 92:
Tries: Dulin 2, Chavancy, Arous, Imhoff
Cons: Carter 3, Goosen
Racing 92: 15 Brice Dulin, 14 Joe Rokocoko, 13 Casey Laulala, 12 Henry Chavancy, 11 Juan Imhoff, 10 Dan Carter, 9 Mike Phillips, 8 Chris Masoe, 7 Yannick Nyanga, 6 Wenceslas Lauret, 5 Francois van der Merwe, 4 Luke Charteris, 3 Ben Tameifuna, 2 Dimitri Szarzewski (c), 1 Eddy Ben Arous
Replacements: 16 Camille Chat, 17 Julien Brugnaut, 18 Cedate Gomes Sa, 19 Manuel Carizza, 20 Antonie Claassen, 21 Johannes Goosen, 22 Alexandre Dumoulin, 23 Maxime Machenaud
Northampton Saints: 15 Ben Foden, 14 Jamie Elliott, 13 Luther Burrell, 12 Tom Stephenson, 11 George North 10 JJ Hanrahan, 9 Lee Dickson, 8 Sam Dickinson, 7 Teimana Harrison, 6 Courtney Lawes, 5 Victor Matfield, 4 Michael Paterson, 3 Kieran Brookes, 2 Mikey Haywood, 1 Alex Waller
Replacements: 16 Matti Williams, 17 Ethan Waller, 18 Paul Hill, 19 Christian Day, 20 Jamie Gibson, 21 Kahn Fotuali'i, 22 Steve Myler, 23 Ah See Tuala
Referee: George Clancy (Ireland)
Assistant Referees: Dudley Phillips (Ireland), Mark Patton (Ireland)
TMO: Marshall Kilgore (Ireland)