Lauret became the third Racing player to score a hat-trick.
Northampton had a 14.
Skosan, DIngwall Con: Biggar, and Furbank.
Racing 92 (28) 45
Tries: Lauret 3, Imhoff 2, and Machenaud 4.
Racing 92 ran in five tries in their opening game of the European Rugby Cup and gave Northampton a reminder of the gap between Europe's elite and the rest of the world.
Flanker Wenceslas Lauret scored three tries for the French side, while Juan Imhoff scored two more.
Fraser Dingwall scored one and set up another for Courtnall Skosan, but Saints were always second best.
The next two European games will be played by Northampton.
Their pool-stage campaign ends with a trip to Paris to play Racing.
Wales fly-half Dan Biggar may be out for a few weeks with a groin injury, and that could be a problem for Chris Boyd.
The first half leaves the Saints with too much to do.
Six points down after five minutes. Thirteen were down after eight. Adrift after 23.
After a good start to the season, Northampton looked overwhelmed by the step up in quality against the three-time runners-up.
Sam Matavesi's chip from in front of his own posts summed up the confusion of the Saints as they gave up a bunch of penalties and plenty of ball.
Racing took full advantage.
Finn Russell snapped the ball back inside to create tries for Lauret and Imhoff.
Northampton were hopelessly narrow in their defence as Russell and Kurtley Beale spun wide to open up a route for Imhoff once more.
England coach Eddie Jones watched as South African wing Skosan scored the only first-half bright point for Saints, squeezing a cute grubber kick through for him.
Russell's showreel score brings down the curtains on the Saints.
The British and Irish Lions were beaten by South Africa in the third Test.
The hopes of Northampton fans that they would entertain at the interval were snuffed out by a brilliant score by Russell in the second minute.
Lauret scored his second try after the Scotland fly-half created a delicious sky-hooking offload for Alex Mitchell to put him in.
Biggar, who started with a strapped thigh and was caught by a big Vakatawa tackle in the first half, hobbled to the touchline shortly after and the game quickly slipped away.
Lauret's hat-trick score was set up by a burst through some flimsy tackling by the manFka.
Many of the home fans headed for the exits after Lewis Ludlam's try was scrubbed off because he was judged to have blocked a potential French tackler with 10 minutes to go.
If they are not to leave the competition quickly, they will need to improve a lot.
Northampton director of rugby Chris Boyd said that they were dominated in the early part of the game. The referee's interpretation made it difficult for us to adapt.
The guys in the sheds are pretty disappointed with the result and the performance, there are some pretty telling lessons there.
"Dan Biggar had carried that thigh for a couple of weeks and he over stretched it in the first half."
Furbank, Hutchinson, Skosan, Biggar, Mitchell, Matavesi, Painter, Ribbans, Moon, Wilkins and Augustus are from Northampton.
Replacements: Sleightholme for Proctor, Hutchinson for Biggar, Matavesi for Matavesi, Fish for Matavesi, Carey for Painter, Wood for Wilkins.
Racing 92: Thomas, Vakatawa, Fickou, Imhoff, Russell, Machenaud, Gogichashvili, Baubigny, Oz, Jones, Le Roux, Diallo, Lauret, Tanga.
Gibert for Thomas, Gibert for Machenaud, Ben Arous for Gogichashvili, Chat for Baubigny, and Moreaux for Jones were replacements.
