There are two different Maseratis used in the film. In the opening scene, there is a different car used for the fast part of the car chase - notably a Quattroporte GTS 4.2 that can be identified by a chrome mesh grill and four exhausts. At the part where they are stopped by the police, a different front grill can be seen with vertical segments, and when they drive off two large exhausts are visible. It is one of the 4.7 versions of the Quatroporte. The 4.7 version of the car is again shown when later Driss gets in the car for the first time.
When Driss is getting ready to leave the mansion after Phillipe fires him he is seen putting the baby monitor around his neck. In the next scene the monitor is gone, and when we see him next in the foyer it's around his neck again.
Driving north to Dunkirk at the end would have taken place in the morning after their night adventure. The sun would have been rising in the east, instead of setting in the west. So, either the time of day is wrong, or the direction they are driving.
When the police car first appears behind Driss, you can hear a short burst of the siren, which is clearly an American-inspired tone (also used in UK etc.) This is not possible, because the French police only use one very recognizable tone. When the pursuit begins, the police car has the recognizable and correct French siren tone.
When Driss is first learning how to care for Philippe, we learn that Philippe can't sit upright by himself. However, the strap that is used to hold Philippe upright in his wheelchair sits so low on his waist that it couldn't possibly support his torso.