In a new decision (4A_289/2018) the Swiss Federal Supreme Court confirms the view taken by Swiss legal scholars that an employer cannot file its claim against an employee at the venue of a branch ("Gerichtsstand der Niederlassung"; Art. 12 CPC). Employers are limited to venues provided for in Art. 34 CPC whereas employees may be entitled to file a claim at the venue of the employer's branch.
The decision of September 28, 2018 can be found here.