Police were forced to close part of Swinegate on Thursday, April 4 after the pane of glass came from the six-storey building.
A Co-op store on the ground floor was closed and cordoned off while police investigated.
3 Sovereign Square only opened in 2017 and offers Grade A office space.
It was developed by Bruntwood and Kier but is owned by Leeds City Council, who bought is for nearly £40million in 2016 as a commitment to investing in the city's economy
In response to the window smash, a spokesman for Leeds City Council said: “A decorative glass panel fractured above the fifth floor of 3 Sovereign Square, breaking into small pieces as it was designed to do in the event of failing.
"The main contractor of the building, glazing manufacturer and risk assessors have all attended the incident and inspected the glazing system to gather all the details to identify the cause of the breakage.
"The on-site 24 hour security team responded immediately, making the areas safe and clean, ensuring public safety until inspections could conclude the area was safe to reopen.
"A full report on the incident will be submitted to the council shortly.”
3 Sovereign Square was built on the site of the old Queen's Hall concert venue, which was previously a tram depot.
After the hall's demolition, the site was a surface car park. Law firm Addleshaw Goddard are the anchor tenants of the development.
Last December, North Brewing Co opened a taproom in one of the development's retail units.