London and Paris, separated by the English Channel, have been rivals since medieval times, and continue to duke it out today for recognition and visits.
In 2019, London was ever so slightly more popular on Google Trends, earning a popularity score of 44 vs. Paris' 39 (you can read about the somewhat complicated way Google Trends determines its scores here).
Moreover, London also reigns supreme in terms of visitors; it welcomes about 20 million tourists a year, vs. Paris' 18 million.
The countries most searching for London all have ties to the city: the United Kingdom, Ireland, South Africa, India and Australia. For Paris, the searches come from France, Iran, Belgium, Brazil and Chile.