Citroen C6 (2017) is 500 mm (19.69 inch) longer and 25 mm (0.98 inch) wider than Mercedes GLA-Class (2020).
Mercedes GLA-Class (2020) is 148 mm (5.83 inch) higher, 253 kg (558 lbs) lighter and has 14 liters (0.49 ft3) bigger cargo space than Citroen C6 (2017).