The Argentine international is set to return to Spanish football following a spell at Italian side Udinese, with Los Che set to financially benefit from the deal.
The 27-year-old scored two goals at the Mestalla across 44 first-team appearances with Valencia during his stint at the club between 2014 and 2016.
El Mundo Deportivo now report that part of the agreement that took him to the Italian club was to retain a 15 percent future sell-on clause for the player.
With De Paul set to join Atleti for a deal in the region of €35m, that means that Valencia would profit €5m from the transfer.
De Paul, who has won 24 international caps with Argentina, has won widespread admirers during his stint in Italy with Udinese and now looks set to join the ranks at Atleti.