Factual error: The assassin sent to kill Captain Renard carries a French passport which lists his place of birth as "Marseilles". This is an old-fashioned spelling of the name now almost only seen in North America. The French spelling is and always has been "Marseille".
Continuity mistake: When Nick goes to see Juliette/Eve, she's in a coma and unable to move and her hand and fingers are lying flat against her belly. In the wide shot of her, her hand is turned and her fingers are somewhat on top of each other, instead of lying flat. It goes back to lying flat in the next shot of her.
Continuity mistake: When Marwan Hanano stops the basketball with his foot, his feet are facing the court, so his left foot is almost perpendicular to the concrete strip. In the next shot, with his right foot still on the ball, his left foot changes position, so it's nearly parallel with the concrete strip.
Factual error: The Czech crime database (which appears to be an official Czech database) is headed 'Czechoslovakia'. Czechoslovakia has not existed since the Czech Republic and Slovakia separated in 1993 and neither country uses the term any more.
Continuity mistake: When the couple is in the boat when the creature appears, the woman is taking a picture and holding her phone in her left hand, she turns around and her left hand is raised and her right hand is on the boat edge. When the camera angle changes, her left hand is now on the boat and her right hand is lowered and holding the phone (confirmed when the camera angle changes again and she's in the same position, holding the phone in her right hand).
Continuity mistake: (Episode 4: Lonely hearts) The woman's body changes position after being hit by the car in the beginning. As the body stops tumbling after the hit, she ends up laying next to the bridge railing, along side it, in the next shot her body lays in the middle of the driving lane, feet toward the mid-line and head towards the railing.
Factual error: Sean Renard is seen going into 'asystole' at the end of the episode (flat lining) and the doctors use a defibrillator to shock his heart, but a defibrillator is useless with asystole. It is only used to correct abnormal heart rhythms (fibrillation). Defib-ing an asystolic heart is like trying to reboot a computer device with no power supply.
Factual error: There is a copy of a Czech passport shown when Renard reads the files sent from Paris. There is a typo in the place of birth which reads "Brastilava" instead of "Bratislava" (capital of Slovakia). Interestingly enough the name of the city is also spelt correctly on the passport just below, where it refers to the place of issue.
Factual error: Rosalee shows an old letter allowing her to contact the "Wesen Council" ; the letter is that of a law firm (Advocatenkantoor) in Amsterdam and the Hague. On the top of the letter instead of the correct inscription "Den Haag" we find "DeHaag" which is incorrect.