Police visited a barbershop after being told it had continued trading during lockdown - and discovered the owner halfway through a cut.
Hairdressers cannot open until July 4 according to current restrictions, as part of stage three of official plans.
But officers had been informed Bob's Gens Hairdresser in Chipping Sodbury was still taking clients and paid a visit.
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But further inspection discovered a man on the premises having his hair cut - and the premises was shut down.
The spokesperson added: "Chipping Sodbury police received a call on Wednesday (June 3), reporting that a local business was open in contravention of the coronavirus guidance.
"Officers did attend and give words of advice to the owner, however local authorities deal with breaches of the regulations by businesses.
"Incidents can be reported to South Gloucestershire Council by emailing foodandhealth@southglos.gov.uk."
A spokesperson for South Gloucestershire Council said: "Based on police evidence we will serve the business with a Prohibition Notice under the Health Protection (Coronavirus, Restrictions) (England) Regulations 2020.
"This Notice has immediate effect requiring the activity to cease and not resume before the end of the emergency period relevant for this type of premises.
"Failure to comply is an offence punishable by a fine in a Magistrates Court."
