Al-Jazeera said it was considering broadcasting videos shot by Mohammed Merah, the Toulouse gunman who killed seven people.
The Paris offices of the Qatar-based television company confirmed it had received a parcel containing a USB memory stick and a letter claiming responsibility for the attacks in the name of al-Qaida.
The package, which was postmarked 21 March - the day that police surrounded Merah's flat - arrived on Monday and has been passed on to the police.
Merah, a 23-year-old Frenchman of Algerian descent, died in a shootout with police following a 32-hour siege at his apartment in Toulouse.
During the standoff with police and Raid commandos Merah claimed responsibility for seven killings, including three children and a rabbi at a private Jewish school in Toulouse.
He told police he had filmed the killings and insisted the videos would be posted online. Witnesses told police the killer had a video camera.
Al-Jazeera management was considering whether to broadcast the images.
"We are not a sensationalist network. We are not looking to broadcast images without measuring the risks and consequences," Zied Tarrouche, the network's Paris bureau chief, told the French news network BFM-TV.
"This is why management will decide today during a meeting in Qatar whether to broadcast this video or not," he said. "We should know in a few hours."
Tarrouche said the 25-minute video presented the attacks in chronological order and had been edited into a montage.
"There was a mixture of religious music and chants, lectures and recitals of verses from the Koran," he added.
French president Nicolas Sarkozy has asked the network not to broadcast the video.
"I ask those in charge of all the TV channels in possession of these images not to broadcast the images under any pretext out of respect for the victims and out of respect for the republic," he said.
Merah's Father Angers France
The controversy surrounding the killings has been further inflamed by the killer's father saying he would sue France over his son's death
"France is a big country that had the means to take my son alive," Mohamed Benalel Merah told AFP. "They could have knocked him out with gas and taken him in. They preferred to kill him.
"I will hire the biggest lawyers and work for the rest of my life to pay [their] costs. I will sue France for killing my son."
Merah's father, who lives in Algeria, said he would bury his son there.
France's foreign minister Alain Juppe told Radio Classique: "If I were the father of such a monster, I would shut my mouth in shame."
The investigation has focused on Merah's brother, Abdelkader Merah, who is suspected of helping the killer prepare the attacks. He has been charged with complicity in the murders.
Abdelkader Merah reportedly told police he was "very proud" of his brother but denies all charges.