CFDP Ltd (trading as Belvoir Nuneaton and Hinckley) along with company director Clayton Foston were taken to Loughborough Magistrates Court by Hinckley and Bosworth Borough Council.
The council's Private Sector Housing Team said they became aware of the offence in 2019, when a former tenant raised concerns about their eviction in April that year.
The unnamed tenant was in hospital while his possessions were removed from his flat and the locks were changed.
Mr Foston, who runs CFDP Ltd which is based in the The Crescent in Hinckley, pleaded not guilty to the offence he was personally accused of and plead not guilty on behalf of his limited company.
The trial took place on Monday 29 March 2021 and the court found both parties guilty under Section 1 of the Protection from Eviction act 1977.
CFDP Ltd was fined £5,000, and Mr Foston received a personal fine of £1,000. Costs for taking the case of £3,472.76 were awarded to the council and a victim surcharge of £290 brought the final bill to the offenders to £9,762.76.
A Criminal Behaviour Order (CBO) was issued to Mr Foston, which restricts his future actions in private rental market.
Victims can also seek civil compensation as a result of the guilty verdict.
Head of Housing for the Borough Council Madeleine Shellard said:
“The council will not accept residents being displaced from their homes and will take appropriate action where it is required. The process for ending a tenancy is set out clearly in law and guidance so there is no excuse for failing to afford your tenants due process.
"While unlawful eviction in Hinckley and Bosworth is relatively rare this case should serve as a warning to those who may be considering it, especially after the last year of restrictions and financial challenges.
"Where a tenant has been displaced without the correct legal procedures having been followed the council will in the first instance look to reinstate the tenancy.”
Belvoir were contacted for comment.