Landlords have been given a month to remove large advertisements from their properties or face a hefty fine.
Owners of the banners – which were mainly student landlord and accommodation firms – have been contacted by the Council reminding them that the ads are governed by outdoor advertisement legislation, even if only put up for a short of time.
About 60 companies and individuals have been sent a letter warning them that their signs are unlawful and breaching planning legislation.
Dozens have cropped up in gardens in and around St Judes, Mutley, North Road East, Mount Gould and the City Centre.
Councillor Patrick Nicholson, Deputy Leader and Cabinet Member for Strategic Housing, Transport, and Planning said: “We have received a lot of complaints from residents who live in these areas. These signs are big, unsightly and spoil the look and feel of streets with unnecessary clutter.
“Most of these signs advertise the fact that the house is occupied by students, who are far more likely to look online for properties anyway.”
The adverts have been erected without consent from the Council, the local planning authority and must be removed before 1 December 2016 or face prosecution with fines of up to £2,500 per advert.
Failure to remove the signs after a conviction can also result in an additional fine of £250 per day.