Bordeaux-Begles drawn with Northampton in Champions Cup final repeat
The French club edged the English outfit 28-20 in May's final and are joined in Pool 4 by the Scarlets, Bristol, Pau and the Bulls.
The other highlight of the group stages pits La Rochelle against Leinster after the French side beat the Irish province in the 2022 and 2023 finals.
Teams will play four games in the group stages, avoiding fixtures against sides from the same league.
The opening round of the season takes place on December 5-7 with the final at San Mames Stadium in Bilbao, Spain on May 23.
The decider for the second-tier Challenge Cup will be held in the same location but a day earlier.
Champions Cup pool draw:
Pool 1: Toulouse (FRA), Clermont (FRA), Sharks (RSA), Saracens (ENG), Glasgow (SCO), Sale (ENG)
Pool 2: Bath (ENG), Toulon (FRA), Munster (IRL), Castres (FRA), Edinburgh (SCO), Gloucester (ENG)
Pool 3: Leinster (IRL), Leicester (ENG), Harlequins (ENG), La Rochelle (FRA), Bayonne (FRA), Stormers (RSA)
Pool 4: Bordeaux-Begles (FRA), Scarlets (WAL), Bristol (ENG), Pau (FRA), Northampton (ENG), Bulls (RSA)
Challenge Cup pool draw:
Pool 1: Ospreys (WAL), Zebre (ITA), Montpellier (FRA), Montauban (FRA), Black Lion (GEO), Connacht (IRL)
Pool 2: Lyon (FRA), Newcastle (ENG), Dragons (WAL), Treviso (ITA), Lions (RSA), Perpignan (FRA)
Pool 3: Cheetahs (RSA), Cardiff (WAL), Exeter (ENG), Racing 92 (FRA), Stade Francais (FRA), Ulster (IRL)