The French carmaker said Tuesday (January 17) it saw a 9.4% drop to just under 1.47 million units sold.
It comes with the automaker in the middle of a turnaround in a drive to lift profits.
It is betting on higher-margin and electric cars to drive growth.
Last year, it said the Renault brand was third in Europe for sales of electrified vehicles, which includes hybrids, behind Toyota and Tesla.
Such sales were up 12% from a year before.
But sales across Renault fell 15% in its top market France, and by a quarter in Germany.
Global sales were down 15% overall.
Renault COO Fabrice Cambolive said he was optimistic things would improve this year.
But he did say recent global price cuts announced by Tesla were an issue for the carmaker.
Renault is currently in talks with Japanese partner Nissan to restructure their alliance.
The group unveiled an overhaul in November that would deepen ties with China's Geely.
It also plans spin off its EV unit through a stock market listing this year.
