The game is a repeat of last year's final, and the home side seek revenge for defeat in the competition's decider in 2021-22.
Match preview
Freiburg's shock 2-1 defeat of Bayern Munich in the previous round meant Christian Streich's team would play in consecutive Pokal finals.
Last year's decider was the club's first in their 119-year history, but they were beaten on penalties after it ended 1-1 following extra time.
While the Breisgau Brazilians seek a return to the cup final this season, they must defeat the side that ended their dream in 21-22.
Having already eliminated Thomas Tuchel's Bayern, Freiburg should be confident of beating a Leipzig side that got the better of Borussia Dortmund in the last eight.
Streich's men are higher than Tuesday's opponents in the Bundesliga table, with a three-game winning run seeing them supplant the Red Bulls into fourth place.
Freiburg have spread the goals around in the competition, evidenced by no player scoring no more than one goal, and they hope that unpredictability pushes them into another final.
Leipzig are favoured to play in another final, having made the deciders in 2021 and 2022, and Marco Rose's men look to retain the title they claimed last year.
Die Roten Bullen will be pleased Christopher Nkunku was back among the goals at the weekend, their talisman scoring for the first time since November 2022 after recovering from a recent muscle injury.
The Frenchman had scored 12 times in the league before Saturday's only goal in the win over Hoffenheim and is the club's top scorer in the Bundesliga despite missing nine rounds.
Leipzig are unbeaten in 10 Pokal games since losing the 2021 final to Dortmund and have made it to this year's semi-final, scoring 17 times and conceding just one.
Their seven-game unbeaten run against Tuesday's opponents and 3-1 league victory over Freiburg in early November means they are fancied to go through to play either Stuttgart or Eintracht Frankfurt in June's final.
Freiburg DFB-Pokal form:
W
W
W
W
Freiburg form (all competitions):
D
W
L
W
W
W
RB Leipzig DFB-Pokal form:
W
W
W
W
RB Leipzig form (all competitions):
L
W
W
W
L
W
Team News
Daniel-Kofi Kyereh has not played for Freiburg since February, and the attacking midfielder is not back from his layoff.
Manuel Gulde was crucial to Bayern's elimination in the previous round, but the centre-back is sidelined with a hamstring injury.
With Peter Gulacsi still injured, Janis Blaswich is expected to continue in goal for Leipzig on Tuesday.
After scoring against Hoffenheim on Saturday, Nkunku should retain his spot in the side for the semi-final.
Freiburg possible starting lineup:
Flekken; Sildillia, Ginter, Lienhart, Gunter; Hofler, Eggestein; Doan, Grifo; Gregoritsch, Holer
RB Leipzig possible starting lineup:
Blaswich; Klostermann, Orban, Gvardiol; Simakan, Kampl, Laimer, Raum; Forsberg, Werner; Nkunku