Sales figures are expected to reach about 3.3 million units this year, although it is likely to experience a drop of 2.9% from the previous year.
Commenting on September's estimated sales figure of 260,000, the study, compiled by JD Power-LMC, said: 'Although rather lower than the August selling rate, this is still a marked improvement on earlier months. Looking at the strategic picture behind the monthly fluctuations, it is becoming clear that German car demand reached a trough in the second quarter of this year, and has been gaining ground steadily since then.'
But, it added: 'Not that the 3.3 million selling rate could be described as strong – but the direction of change is looking more encouraging than it has for some time.'
The report found that France's September sales, which reached 153,303 units, were virtually identical to the year-earlier figure.
'This came as a considerable relief, bearing in mind the alarming low volume of sales registered in August. It now seems clear that the underlying level of demand remains reasonable robust, though still tending to weaken gradually, just as it had been prior to the poor August result.'
Interest surrounding the Paris Motor Show may stimulate public interest, the report suggests.
Spain experienced a 'mildly positive outcome' with the selling rate remaining at 1.4 million units a year, exactly as it has in the last four months.
Sales in Scandinavian countries, except Norway which had a disappointing month, the survey says, continued to rise fairly strongly.
'The Swedish result in particular confirmed the significant upswing that has been gaining momentum there throughout the last year,' it added.