The winner of Tuesday's clash, which will be the first ever meeting between PSG and Leipzig in European competition, will take on either Bayern Munich or Lyon in the final on August 23.
Here, Sports Mole looks at how PSG could line up in Lisbon.
It would be fair to say that there are a number of unknowns when it comes to team selection for this match, with PSG boss Tuchel capable of springing surprises in terms of both formation and personnel.
Layvin Kurzawa is still unavailable with a thigh problem, while Marco Verratti is also unlikely to return, with the Italian midfielder losing his battle to recover from a calf issue.
There is expected to be a change between the sticks, meanwhile, with Keylor Navas's thigh problem that he picked up against Atalanta likely to rule him out, meaning a probable start for Sergio Rico between the sticks.
Angel Di Maria was suspended for the quarter-final clash but will return to the XI for this game, while Kylian Mbappe made his recovery from an ankle injury off the bench against Atalanta, and the France international should be ready to return to the attack.
Leandro Paredes could get the nod over both Ander Herrera and Idrissa Gueye to start in a midfield two with Marquinhos, although Tuchel also has the option of reverting to a back three, allowing Neymar, Mbappe and Di Maria to start in a three-pronged attack, with Mauro Icardi dropping out.
It seems likely that Di Maria and Neymar will support Icardi and Mbappe from the wide areas, though, with Herrera, Gueye and Pablo Sarabia losing their starting spots from the quarter-finals.