Luis Enrique's PSG, who beat Premier League champions Arsenal on penalties in the Champions League final in May to retain their title, will host Barca and travel to City. Their other league-phase opponents are Roma, Aston Villa, Galatasaray, Villarreal, Slovan Bratislava and Como.
The league-phase format, introduced in the 2024-25 season, is entering its third campaign.
Real Madrid host Inter and travel to Arsenal. They will also face PSV Eindhoven, Roma, RB Leipzig, Shakhtar Donetsk, LASK and AEK Athens.
The meeting with Inter will see new Real manager Jose Mourinho face one of his former clubs. Mourinho, who returned for a second spell in charge of Real in June, guided Inter to the Champions League title in 2010 before leaving for the Santiago Bernabeu.
Six-time European champions Bayern Munich's headline fixtures include a home game against Arsenal and away trips to Atletico Madrid and Manchester United.
Under new manager Andoni Iraola, six-time European champions Liverpool will face Inter and Atletico among their standout league-phase fixtures.
The Premier League and LaLiga are the most heavily represented leagues in this season's competition, with five clubs each.
England's contingent comprises Arsenal, City, United, Villa and Liverpool, while Spain will be represented by Barca, Real Madrid, Villarreal, Atletico and Real Betis.
United return to Europe's elite club competition after a two-season absence and face a tricky draw that includes a trip to Atletico and home games against Bayern and Roma.
The league phase begins on September 8, with 36 teams competing across eight matchdays through January 27.
The knockout stage starts in February, with the final set for June 5 at Atletico's Metropolitano Stadium. The venue will stage the Champions League final for the second time, having previously hosted Liverpool's 2-0 victory over Tottenham Hotspur in 2019.
While Atletico will host the final, they appear to have been handed one of the competition's toughest league-phase draws, with Bayern and United due to visit Madrid and a trip to Liverpool also on the agenda.
