Saturday's game was halted after 31 minutes while Lopes received treatment, having been felled inside his area by a number of pyrotechnics thrown from the stands at Stade Saint-Symphorien.
The Portuguese shot-stopper was then forced to turn away quickly as a firecracker exploded on the ground close to his head, while Metz players urged those responsible in the crowd to stop.
After a 45-minute delay, the match was finally abandoned, with Lyon confirming via Twitter that they refused to resume as "security cannot be guaranteed".
The club later said that Lopes had been taken to hospital for check-ups.
"The public authorities in Metz took the decision to stop the match between FC Metz and Olympique Lyonnais indefinitely, in agreement with the match delegate and the referee, following the incidents that took place at the half-hour point of the game," French football's governing body, the LFP, said in a statement.
"A report will be sent to the LFP's Disciplinary Commission. The LFP regrets these incidents and will be uncompromising in its continued review of this report."
Anthony Lopes est en direction de l'hôpital pour passer des examens. #FCMOL— Olympique Lyonnais (@OL) December 3, 2016
Metz had been leading 1-0 at the time of the incident, but Lyon could be awarded a 3-0 victory by default, depending on the decision following the LFP's review.
A similar incident occurred last month, when Poland striker Robert Lewandowski required treatment after what appeared to be a firecracker exploded near his feet during his side's 3-0 World Cup qualifying win over Romania.