Holders Liverpool face Italy's Napoli, Austria's Salzburg and Belgian champions Genk when they start the defence of their Champions League title.
The group stage draw in Monaco on Thursday also pitted German champions Bayern Munich against last season's losing finalists Tottenham Hotspur, Greek side Olympiakos and Red Star Belgrade.
Spanish champions Barcelona face Bundesliga runners-up Borussia Dortmund, Italy's Inter Milan and Slavia Prague in one of the toughest-looking groups.
Premier League champions Manchester City are up against Shakthar Donetsk, Dinamo Zagreb and Italy's group-stage newcomers Atalanta.
Thirteen-time European champions Real Madrid clash with Paris Saint-Germain and also face Club Brugge and Galatasaray
Italian champions Juventus are in a group with Atletico Madrid, Bayer Leverkusen and Lokomotiv Moscow.
Chelsea, Ajax, Valencia and Lille are together, while Zenit St Petersburg, Benfica, Lyon and RB Leipzig are paired in the remaining groups.
The first matches will be played on Sept. 17-18. The final matches of the group schedule will be played on Dec. 10-11.
The 2020 UEFA Champions League final will return to Istanbul for the first time in 15 years this season.
It will be played in Istanbul's Atatürk Olympic Stadium on May 30.
Inaugurated in 2002, Atatürk Olympic Stadium will host its second Champions League final after the one in 2005 between Italy's AC Milan and England's Liverpool.
The draw for the group stage of the 2019-20 Champions League made on Thursday:
GROUP A
Paris St Germain
Real Madrid
Club Brugge
Galatasaray
- - -
GROUP B
Bayern Munich
Tottenham Hotspur
Olympiakos
Red Star Belgrade
- - -
GROUP C
Manchester City
Shakhtar Donetsk
Dinamo Zagreb
Atalanta
- - -
GROUP D
Juventus
Atletico Madrid
Bayer Leverkusen
Lokomotiv Moscow
- - -
GROUP E
Liverpool
Napoli
Salzburg
Genk
- - -
GROUP F
Barcelona
Borussia Dortmund
Inter Milan
Slavia Prague
- - -
GROUP G
Zenit St Petersburg
Benfica
Olympique Lyonnais
RB Leipzig
- - -
GROUP H
Chelsea
Ajax Amsterdam
Valencia
Lille
