Gasquet pictured arriving at the hearing in Lausanne
Richard Gasquet is expected to learn within the next four weeks whether he will receive a tougher ban for "inadvertently" taking cocaine.
Gasquet received a 12-month ban in May, but in July was cleared to return to the circuit by an independent tribunal.
The 23-year-old Frenchman has played 17 matches since returning in August.
However, the International Tennis Federation wants the Frenchman to receive a longer ban and has appealed to the Court of Arbitration for Sport.
Tuesday's hearing on the appeal, which Gasquet attended, took place in Lausanne, Switzerland, and a decision is likely in early December.
"Everything went as expected and Richard Gasquet has, of course, had his chance to speak," Cas secretary-general Matthieu Reeb said after the seven-hour hearing.
"Now the arbitrators will begin their deliberations, which are going to take around three to four weeks until a final judgment will be communicated to the parties."
Gasquet has previously said that the drug got into his system after he kissed a woman in a nightclub in Miami.
The tribunal supported his claim and felt that because "no more than a grain of salt" was recorded in the sample a long ban would have been an injustice.
Unhappy with the ruling, the ITF, who wanted a one to two-year ban, and the World Anti-Doping Agency (Wada) appealed to Cas against the tribunal's decision.
Gasquet tested positive following a urine sample at the Sony Ericsson Open in Florida in March, after he withdrew from the tournament because of a shoulder injury.