The Eagles will face FC Girondins de Bordeaux, APOEL FC and Maccabi Tel Aviv FC in their group, while Christian Streich's Freiburg will play Sevilla FC, G.D. Estoril Praia and FC Slovan Liberec.
"I don't know enough about Liberec and Praia to estimate how strong they might be," Streich said. "The players are just over the moon to be involved in the competition. I would have been delighted as a player as well."
Frankfurt chief executive Heribert Bruchhagen commented: "All four teams are of equal quality - there aren't any favourites or underdogs in our group. I am delighted for our fans that we don't have to travel too far for our away fixtures."