Bafin, Germany's financial watchdog, said Maple had to set aside funds to cover unpaid taxes and that was threatening its financial position.
Maple Bank's German arm came to the attention of the public in 2008 when it helped Porsche in its attempt to takeover Volkswagen.
The attempt failed, and in 2009 the tables were turned when Volkswagen took over the sports car maker.
In September German prosecutors searched Maple Bank offices in an investigation into tax evasion and money laundering.
At the time it was reported that authorities were looking into allegations that bank staff had illegally claimed back more than â‚¬100m ($110m; Â£76m) in tax.
But Sunday's announcement from the financial regulator made no mention of that case.
Maple Financial Group is an investment bank. Bafin said its German unit had been barred from taking payments that were not related to paying off debts.
The unit has â‚¬5bn in assets, according to Bafin. Its failure does not pose a threat to financial stability, the regulator said.
The German arm of Canada's Maple Bank has been closed by German authorities.