The French club entered the group stage directly.
In the current Europa League, only those teams remained that secured a ticket to the Champions League through the domestic championship.
In this case, UEFA sends to the group instead of the winner of the Europa League the third team of the fifth association, which turned out to be Rennes.
This means Rennes will not qualify for the Champions League, but will go directly to the group stage. The French club will definitely not be a rival to Dynamo Kiev on the way to the group.
Note that possible rivals of Dynamo in the third round are AZ, Viktoria Plzen, PAOK, Lokomotiva Zagreb, Rapid Vienna and Ghent.