Dozens warned in Derby cycle crackdown
The first day of a crackdown on cyclists using pedestrianised areas of Derby saw 65 people stopped.
City council officials and community support officers gave verbal warnings but said £30 fines would be issued after two weeks.
The council said it was responding to complaints from families and vulnerable people who felt bicycles were sometimes being ridden dangerously.
Campaigners said they were concerned responsible cyclists would be targeted.
The council said maps of approved cycle routes were widely available.
Councillor Chris Poulter denied the move would discourage all riders.
"I want to emphasise it is only the odd few. You see some with all the gear and you would think they were on a timed stage of the Tour de France," he said.
"People in the city centre - and I have been guilty of this myself - in a pedestrianised zone switch off to vehicles and you are not aware, and people who are hard of hearing or with mobility problems do have problems getting out of the way."
David Clasby, from transport charity Sustrans, said while the city had a good network of cycle routes, the initiative may send the wrong message.
"The big concern that we have got is that it will be misinterpreted as a negative thing towards cyclists," he said.
"There are a lot of people who do unfortunately cycle irresponsibly and we want to target the irresponsible people.
"But there are plenty of people who use the city centre, particularly out of office hours, who cycle perfectly responsibly and our fear is they may be targeted also."