Dembele left the PSG ranks for Fulham in 2012 and has come to prominence in the Championship this season with 12 goals in 36 league games.
Tottenham were heavily linked with the striker's signing in January and have been tipped for a move in the off-season, when Dembele's contract is set to expire.
But Dembele suggests Mauricio Pochettino may be forced to look elsewhere if PSG come calling.
"Like every Parisian, I dream of playing for PSG," Dembele told L'Equipe. "Why could it not happen some day? If they want me...
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"I left in 2012 when [Zlatan] Ibrahimovic and [Ezequiel] Lavezzi joined the club. I would have gotten little playing time. PSG were not counting on me.
"I know that some players have gotten their chance since, like Jean-Kevin Augustin, but I preferred to leave and try my luck elsewhere."
Dembele was part of the same generation as Bayern Munich winger Kingsley Coman at PSG and he has only good memories of his time at the Paris club.
"We went through some great moments together," he added. "I have nothing but good memories. I learned everything I know at PSG.
"We were unbeatable. At some point, we had a team with [Mike] Maignan, [Adrien] Rabiot, [Hervin] Ongenda, Kingsley and myself!"