Sources added that the veteran defender agreed to join the Ligue 1 giants on a two-year deal.
Ramos, 35, announced last month that he would leave Real Madrid after failing to reach an agreement to extend his 16-year stay in the Spanish capital.
Ramos didn't strike an agreement with Madrid due to discrepancies over the length of the deal. Los Blancos were only willing to offer one year and by the time Ramos agreed to accept the club's proposal he was told the deadline had expired.
Ramos had wanted a two-year deal. His wages at PSG are set to be lower than what he was earning in Spain and what he would have earned had he stayed at the Bernabeu.
Ramos will land in Paris just hours after the arrival of his former Real Madrid teammate Achraf Hakimi. Hakimi, 22, is expected to join PSG on a €70m transfer from Inter Milan, sources have told ESPN.
Pochettino was eager to strengthen his defensive line that proved to be their weak spot last season when they were eliminated by Manchester City in the semifinal stages of the Champions League.
ESPN's Julien Laurens contributed to this report.