While the 607 earned its four stars, it did not perform as well as some other large cars have done. The driver's sill and the door pillar were found to be unstable after the frontal impact and the door no longer fitted its opening. The loads acting on the driver's chest in both tests were high and the areas his knees might strike were unforgiving. Meanwhile, its performance in the side impact was good, but not among the best. Both children ran the risk of chest injury, and protection for pedestrians was poor.
The driver and passenger were reasonably well protected. Impact forces fed into the passenger compartment caused its sill to buckle and the door pillar to rotate outwards. Afterwards, the door could not be opened by hand. The driver's head and neck were well protected but the forces affecting his chest were high for a large car. Also, loads were fed into his shin below the knee, which can cause disabling injuries. The centre rear belt was of a three-point type that gives better protection than a lap-only belt.
The 607's head-curtain and thorax airbags suggest it is capable of giving excellent protection but while it achieved a good standard, other similar large cars have done better. That said, the airbag curtain provided good head protection for those in the front and rear.
There is a manual switch to turn off the passenger's airbag. There are labels to indicate this, they could peel off, and did not warn of the danger of death or serious injury if a rear-facing restraint was put on the front passenger's seat with the airbag active. There is just one set of ISOFIX anchorages provided; so only one of the seats could use it although both were approved to do so. The seats were also approved to use a top tether with the ISOFIX anchorage but the car is not fitted with the necessary attachment. Both seats performed patchily and the children risked chest injury from the frontal impact.
Peugeot says it built protection into the 607 at the design stage. But its results did not impress.