The killer aka the Truth Terrorist uses a Beretta 92FS as his main sidearm in the show. A gangster is armed with the 92FS in the eighth episode.
Glock 17
A Glock 17 is used as the main sidearm of a Direction centrale du renseignement intérieur (Central Directorate of Homeland Intelligence) agent before Fabien Vincent (Thierry Frémont) disarms the agent and uses it to get away from DCRI custody in the eighth episode. A few Northbourne Constabulary plainclothes firearms officers are armed with Glock 17s when they confront a teenager near the end of the ninth episode.
Heckler & Koch USP
Fabien Vincent carries a Heckler & Koch USP near the end of the eighth episode after releasing Detective Wassermann.
Mauser C96
DCI Karl Roebuck (Stephen Dillane) takes his fathers old Mauser C96 in the middle of the tenth episode after he is "forced" to be taken off the TT case. He later uses it in a confrontation with the Truth Terrorist before Elise confiscates it.
SIG-Sauer P226
Brigade criminelle (Criminal Brigade) Detective Elise Wassermann (Clémence Poésy) uses the SIG-Sauer P226 as her main sidearm throughout the show.
SIG Pro SP 2022
The SIG Pro SP 2022 is used as the main sidearm for the majority of French National Police officers. The Truth Terrorist seemingly uses one when disguised as a National Police Compagnies Républicaines de Sécurité (Republican Security Companies) anti-riot officer near the end of the sixth episode.
X26 Taser
The Truth Terrorist uses a X26 taser pistol in the third episode to kidnap an elderly French Army veteran, in France.
Submachine Guns
Heckler & Koch MP5A2
Some of the armed Recherche Assistance Intervention Dissuasion (RAID) officers in a hostage rescue operation use Heckler & Koch MP5A2s outfitted with Surefire taclights mounted via picatinny railings near the end of the fourth episode.
Heckler & Koch MP5A3
Some of the armed RAID officers in the hostage rescue operation use Heckler & Koch MP5A3s with folding stocks and taclights near the end of the fourth episode. A few of them have EOTech sights mounted on the upper receiver via picatinny railing. Specialist Crime and Operations Specialist Firearms Command (SCO19) operators are armed with MP5A3s in the middle of the tenth episode.
Assault Rifles
Heckler & Koch G36C
A RAID officer is armed with a Heckler & Koch G36C during a hostage rescue operation near the end of the fourth episode. A few British anti-firearms officers are seen armed with G36Cs with EOTech sights mounted on the picatinny railing when they are called to disarm an IED trap near the end of the ninth episode. A few SCO19 operators are armed with G36Cs outfitted with EOTech sights during a raid on Ashton's hideout in a hostage rescue mission and at the British side of the Channel Tunnel.
Fabien Vincent (Thierry Frémont) appears to use a Mossberg 590 Cruiser to defend himself and Detective Wassermann from gangsters in the eighth episode.
Grenade Launchers
Heckler & Koch HK69A1
A Heckler & Koch HK69A1 grenade launcher is used by the CRS when they launch a raid on an apartment complex near the end of the sixth episode to rescue a kidnapped National Police officer.
Ramo RT-37
A tactical officer is armed with appears to be a Ramo RT-37 riot control launcher in (S1E06).