France could become the largest economy in Europe within a generation, according to a new study conducted on behalf of the German government. This shift in economic dominance is the likely consequence in the difference in birth rates between the two countries.

The study, conducted by leading economic research organisation the Institut der Deutschen Wirtschaft Köln, suggests that by 2050, Germany, Europe’s most populous nation and its largest economy, will experience a population decline of more than ten million, from 81.9 million to 71.4 million people. During the same period, France’s population is expected to grow from 62.6 million to 78.9 million people. By 2050, almost a third of Germans will be over 60, which will exert pressure on pension and healthcare services and reduce the proportion of economically active people.

At present, Germany’s average birth rate is 1.4 children per woman, while that of France is 2.07. The difference has been attributed to the latter’s promotion of child-friendly policies since the 1960s, favourable tax rates for families and an influx of five million immigrants, many of whom are Muslims of North African descent, who have a higher birth rate than the national average.

“Even if birth rates [in Germany] start to rise now, the problem will still hit in 20 years,” said the study’s author, Axel Plünnecke. “It is already too late to stop it from happening.”