Can a merchant charge me extra when I pay by credit card?

On several occasions, I was charged a markup because I used a credit card to pay. Are shops and restaurants allowed to charge extra if you pay by credit card?

Merchants are only required by law to accept actual Swiss francs in cash. All other means of payment provided by third-party service providers, such as checks, credit cards, debit cards, REKA checks, payment via postal deposit slip, Western Union transactions or bank transfers can be accepted by merchants at their discretion.

However, merchants have every right to impose conditions for accepting non-cash payments, such as minimum transaction amounts. They are also free to pass the cost of accepting these transactions on to the payer in the way of markups.

In Switzerland, merchants which accept debit cards (like Postfinance cards and Maestro) generally do not charge a markup when you use these to pay, although some only accept debit cards for payments above certain minimum amounts. Markups on credit card transactions are more common because processing credit card transactions is more expensive.