The 36-year-old David Ashley Construction employee, originally from Romania, was working in a building under construction at De Montfort University. He was dismantling falsework when the accident happened on 15 June 2015.
The Health and Safety Executive launched an investigation and found there was an unsafe system of work and inadequate supervision.
David Ashley Construction was fined £20,000 after it admitted breaching Regulation 4(1) of the Work at Height Regulations, which require employers to plan and supervise work at height properly and ensure it is safely carried out. The company must also pay £1,776 in costs.