Similar covenants that were intended to bind an employee to a company after it supported or (co-)financed off-job education have been ruled on by the federal court. The FC limited the duration of such a covenant to 24 months, with a penalty of not more than 500.- per month. Each month of employment would work off one of those up to 24 months.
This seems worth mentioning, just to demonstrate how narrow the wiggling room is for covenants that are intended to limit the employee's options. IIRC the case was on an IT in finance, one of the best paying sectors.
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Unless OP's top management there's pretty much no way for an employee to be bound by a non-competition clause when the contract ended during the trial period. After all that's what it is for. "Potential clients" is basically everybody, effectively the clause is a ban on employment.
The Federal court ruled on this case , among others:
Marketing assistant, probably employed for more than 5 years because the contractual notice period was 3 months. The noncompetition clause read, paraphrased,
"no competing activity, whether for herself or an employer, swisswide, for 3 years, otherwise a 30'000 penalty is due".
From the deliberations:
"The non-competition clause is only binding if the employment relationship gives the employee insight into the clientele or into manufacturing and business secrets and the use of this knowledge could significantly harm the employer (Art. 340 Abs. 2 Code of Obligations)."
and
"The insight into manufacturing and business secrets must concern specific technical, organisational or financial issues which the employer wishes to keep secret. Knowledge that can be acquired at any company in the same industry is not sufficient."
and further
"A simple employment in marketing, which is connected with an assignment in the "planning, implementation and control of company activities", is in any case not sufficient to be able to prohibit without further ado the use of the technical, organisational or financial skills acquired in a competing company."
(translations by deepl)