May sales dipped slightly to 1.15 million vehicles, dragged down by a sharp fall in France and Germany. But the drop was not viewed as heralding more trouble.
Sales this year still are expected to recover in both countries, and rise moderately in the entire Western European market.
Last month, makers with the newest products outperformed the rest.
Top performers included the Volkswagen Group's Seat and Skoda, Fiat, Jaguar, Nissan, Honda and Volvo.
Brands that fell included VW, Opel/Vauxhall, Ford, Peugeot, BMW and Mercedes-Benz. Most of these marques have older vehicles or depend heavily on Germany for sales.
The decline in Germany of nearly 13 percent was blamed on a good April.
VW had announced a price increase for May 1.
Tax incentives could change the picture in Germany soon. As of July 1, cars without catalytic converters and those that emit higher levels of pollution will be heavily taxed. This is expected to push new-car sales.
'It's a transfer from the old car market to the new. The tax will have some of the same effects as French or Spanish government incentives,' said John Lawson, an analyst at Salomon Brothers in London. 'This is the German stick rather than the French carrot. It penalizes people with old cars and encourages them to buy new ones through the tax system.'
Last year France offered an incentive to scrap an old car.
The 23 percent slump in France partly reflects the absence of that incentive, but it also reflects the Socialist Party victory in national elections.
'France will begin to approach normal numbers. This has been a hangover,' said Lawson.
Italian incentives pushed that market up 43 percent. But the Fiat Group, whose sales in Italy went up an estimated 41 percent, did not see the highest increase. Sales of Opel products went up about 51 percent, Ford rose about 42 percent, PSA sales were up 58 percent, and Renault jumped 49 percent.
VW continues to lead the European market, but its sales show sharp drops for the Golf - which will be replaced this fall - and the entry-level Polo.
Ford's Fiesta and Escort sales fell dramatically despite heavy incentives and price adjustments in key markets such as Germany. Ford did chalk up more than 15,000 sales of the Ka, which is believed to be heavily cannibalizing the older Fiesta. Sales of the Mondeo were flat, despite a facelift and new engines.
General Motors' Astra is suffering a fate similar to that of the VW Golf. Sales are down because of the vehicle's age. The Corsa, into its fifth year, is holding strong with flat sales. The newer Vectra and Omega were both down.
Sales of Fiat's Bravo/Brava are beginning to decline. The Punto was up by more than 10,000 units, and sales of the aging Cinquecento also rose. Both vehicles benefit from Italian incentives, which provide a bigger percentage discount on the cheapest cars.
Nearly every brand in the PSA Group declined, reflecting the sales situation in France.