The below linked Ct. Lucerne WIRA (RAV) brochure notes (translated):
"Professional and local compensation
If the insured person earns an interim salary in a control period that does not correspond to the usual professional and local rate, the salary earned by the insured person will be increased to the usual professional and local rate for this employment when it is taken into account by the unemployment insurance fund.
In determining a standard professional and local rate, reference is made to collective labor agreements, wage recommendations from associations, but also on inquiries with other employers.
If, however, the employer and the employee agree on a wage that is too low - in the sense of wage dumping - the unemployment insurance must, for its part, apply an approach and locally customary rate for the activity performed that is customary in the profession and location when paying the insured person.
By offsetting to a level customary in the profession and location, wage dumping at the expense of the unemployment insurance is prevented.
Under unemployment insurance law, there is no obligation to accept interim earnings that are not compensated at a level that is customary for the occupation and location. Such an activity can be rejected or terminated without sanction by the unemployment insurance fund.
Example
Max Muster, a qualified bricklayer, lost his job at the his employment with the company K. He registered for unemployment benefits.
Mr. Muster met the eligibility requirements, the Fund calculated an insured income of CHF 5,500.00 and a daily allowance of 80%. This leads to average unemployment insurance benefits of CHF 4,400.00 (5,500.00 x 80%).
In April, Mr. Muster is able to start an interim job as a bricklayer at the company P.. The employer pays Mr. P. an hourly wage of CHF 20.00, which, with the 150 hours worked, results in compensation of CHF 3000.00 gross. However, according to the GAV Bau agreement, Mr. Muster's hourly wage amounts to at least CHF 27.55.
When paying Mr. Muster in April, the fund does not calculate an income of CHF 3000.00, but of at least 4,132.50 (150 x 27.55). This income, based on the specifications of the GAV Bau, is binding for the unemployment fund. The deduction of the usual professional and local income leads to considerably lower daily allowance payments."
https://wira.was-luzern.ch/fileadmin..._Praktikum.pdf