India is also closing the gap with China and will eventually overtake it in the second half of the century.
Britain will move up to take fourth spot and Brazil will complete the top five.
According to the report, Europe's third and fourth largest economies will be replaced by India and Brazil in the G8 over the next 15 years.
As Brazil and India meet the political criteria for membership of the exclusive G8 club of developed democracies, their ascension could see France and Italy kicked out of the group, or the club expanded to a G10 as more economies join, the report says.
The UK meanwhile is set to become the best performing economy in the western world over the next 15 years, boosted by its leading position in global software and IT sectors.
The CEBR said France's “dire” economic prospects will see it fall from the world's 5th to 9th largest economy by 2030. Italy - currently 8th in the global league table - is also going through tough times.
Since joining the euro in 2000, GDP growth has remained flat, making it the slowest growing economy of any major developed nation.
Germany's population is likely to be over a million larger than last year's assumption because of migration, from Syria especially. As a result, its GDP is no longer likely to be overtaken by the UK by 2030, although CEBR expect this to happen during the following decade (SH)
Fibre2Fashion News Desk - India