EV shares slid in premarket trading.
Nio fell over 4%; Li Auto fell 2%; XPeng up 0.3%.
The European Commission will notify car makers on Wednesday that it will provisionally apply additional duties of up to 25% on imported Chinese electric vehicles from next month, the Financial Times reported, citing people familiar with the matter.
Analysts have said they expect tariffs of between 10% and 25% on Chinese EVs. The European Commission has said Chinese EVs receive excessive subsidies.
The EU and China's foreign affairs ministry did not immediately respond to Reuters' requests for comment.
Less than a month after Washington quadrupled duties for Chinese EVs to 100%, Brussels is expected to set almost certainly far lower tariffs for imports from Chinese makers such as BYD and Geely as well as Western producers such as Tesla that export cars from China to Europe.
BYD, Geely, SAIC and Tesla did not immediately respond to Reuters' queries on the report.
The move comes as European automakers are being challenged by an influx of lower-cost EVs from Chinese rivals.
China has rebuked the EU over the anti-subsidy investigation, urged cooperation and lobbied individual EU countries, but not fully spelt out what its response to tariffs would be.