Italian great Buffon left Serie A champion Juventus for PSG as a free agent at the end of the season and the 40-year-old started the first three matches of the Ligue 1 campaign.
However, Buffon has since taken a back seat to France international and PSG academy graduate Areola in the last three games and Tuchel is likely to stick with the 25-year-old.
"Yes I chose. The decision is not final but I told Alphonse that he was in my opinion in pole position to be number 1," Tuchel said.
"He comes from the academy. PSG is everything for him. And he absolutely wants to prove himself to PSG. This is a situation that must be respected and capitalised on. We must be proud to have players of this nature, we need this type of players who have the soul of PSG, who embody the club.
"We have a different situation with Gianluigi Buffon, a legend, an idol of Alphonse who is at his side. Both players have very strong personalities. We will have to fine-tune things. Gigi knows it, Alphonse knows it, if you get there, in this configuration, to be smart and generous with both, I'm sure we'll be rewarded. And I'm sure that Alphonse will not be good despite Gigi but thanks to Gigi."
Tuchel said: "Gigi is not just a player on the bench. On a daily basis, he is a player who has a very big influence on the team, he played brilliantly against Guingamp for example, he saved us in the second half, he is on the bench because Alphonse needs to take minutes.
"Gigi would have the right to cross his arms on the bench and watch the game but he does not support it! It's frenetic! He is present, he communicates with the players, tries to help me... and you understand why he is at the top and has such a career."
Ligue 1 titleholder PSG is back in action against Saint-Etienne after the international break on Saturday (AEST).