The method in the latest killing, where the victim was shot with a 9mm round by a gunman who fled on a scooter, recalled that of an Islamist extremist shot dead by police in southern France last month after he committed seven murders.
While nothing yet suggests any political or religious motives in the Paris area shootings, police think there might be a link to several other homicides in the same region of the southern outer suburbs in the past five months.
"That is a concern, but in any case, as in every criminal inquiry, we are putting every effort into finding out who is behind this," said Gueant, in an interview with Europe 1 radio.
On Thursday, a woman of Algerian origin was shot dead in the foyer of her apartment block, part of a working-class housing estate in the Grande-Borne district of Grigny, south of the capital.
Last month, on March 19, an 81-year-old man was killed by a shot to the head with a weapon of the same calibre in the entrance to a similar block of flats in Grigny's neighbouring suburb of Ris-Orangis.
This followed two similar murders in February and on November 27 last year, both in nearby Juvisy-sur-Orge, although Gueant said that a suspect had been arrested for the first shooting and was in jail before the latest.
"That said, this series is worthy of all our attention and we have put all our means behind it," Gueant said.
Last month, the southern city of Toulouse was shocked by a string of seven killings by Mohamed Merah, a 23-year-old Frenchman from an Algerian family who declared himself to be a supporter of the Al-Qaeda militant network.
Merah killed three off-duty paratroopers, three Jewish schoolchildren and a trainee rabbi before he was cornered in his apartment and killed in a shootout with police.