Kensington, Knightsbridge and Notting Hill all saw drops of more than 4% in rental values.
In contrast areas in the inner suburbs including Wandsworth, Clapham and other family friendly areas such as Hampstead and Greenwich grew significantly.
Each saw rental prices increase by at least 4%, with Greenwich seeing an average increase of 16%.
Marc von Grundherr, lettings director of Benham & Reeves Residential Lettings, said: “Although the data showed some mixed results, the overall picture is of a strengthening British economy.
“Rental values are increasing in areas favoured by middle class families while areas that previously attracted numbers of foreign tenants are not seeing the same sort of demand. Sterling’s value is increasing against most foreign currencies so tenants are negotiating more keenly on rent.”
Part of northwest London such as St John’s Wood and Regent’s Park also saw steep drops, while central areas such as Westminster, Mayfair and Belgravia saw rental values flat line.
Up and coming areas of East London only saw modest growth while the Peckham area, recently tipped as a new family friendly area, enjoyed strong growth of 7.69%.