Registrations of Nissan and Ford vehicles dropped steeply as the overall European passenger car market fell 3.6 percent in March.
New-car sales in the EU and EFTA countries declined to 1.77 million last month from 1.84 million a year earlier, industry association ACEA said.
Nissan deliveries were down 29 percent, broadly in line with their decline for the first quarter as a whole, as the Japanese brand reins in less profitable sales to car rental firms and other heavily discounted channels.
Ford, which is restructuring its European operations to address a weak European performance and the looming regulatory emissions hurdles, saw March registrations drop 16 percent.
Other brands with steep declines were Alfa Romeo, down 45 percent, and Porsche and Honda, both down 21 percent.
Volkswagen Group, Europe's No. 1 automaker, saw registrations drop nearly 1 percent, with VW brand's volume down 3 percent, Skoda sales flat, Seat sales up 5.4 percent and Audi gaining 2.8 percent.
PSA Group sales declined by 1.7 percent with Citroen's 6.9 percent gain failing to offset declines of 27 percent at DS and 4.4 percent at Peugeot.
Renault Group sales rose 2.1 percent, boosted by a 22 percent rise in Dacia's volume. Renault brand sales fell 5.6 percent.
Fiat Chrysler Automobile sales fell 12 percent, with Fiat brand down 12 percent and Jeep sales up 3.9 percent.
- Download PDF here for March sales by automaker group and brand
Overall, European registrations for the first quarter fell 3.2 percent to 4.14 million.
The auto industry is facing a downturn in European demand just as it struggles to make drastic cuts to average fleet carbon dioxide emissions or face massive fines.
"An improvement in new car registrations isn’t on the horizon in light of the bleaker economic environment, the endless Brexit debate and political risks," EY consultancy said in a report.
Reuters and Bloomberg contributed to this report