The owner of Westfield Shopping Centres is being bought for $24.7bn (£18.5bn) in a deal that will see the malls launched in new markets.
There are 35 Westfield shopping centres in the UK and the US, while Unibail-Rodamco has 71 sites in Europe.
Unibail-Rodamco said the takeover would result in a "progressive roll-out of the world famous Westfield brand".
The takeover is the second major deal involving shopping centre owners to emerge in just over a week.
On 6 December, Hammerson, which owns the Bullring in Birmingham, announced a £3.4bn bid for Intu, whose properties include the Arndale shopping centre in Manchester.
The deals come as owners of shopping centres face increasing competition from the shift to shopping online.