Although business entertaining is by no means uncommon in Switzerland, there is not as strong a business entertaining culture as some other, more southern European countries.
You are much more likely to be invited out for lunch than for dinner or breakfast. As with many other more northerly European cultures, the Swiss make a fairly strong separation between their work life and their private life — and so prefer to keep any business entertaining within the confines of normal working hours.
Thus entertaining will usually take place at a good restaurant at lunchtime. During the meal, it is possible to talk about business, but it might be wisest to delay introducing work related issues until the host raises the matter.
If invited out for a meal, the host will always expect to pay. Similarly, if you invite someone for a business lunch, you will be expected to pick up the bill.
As a highly regionalized country, the types of cuisine on offer vary from district to district and the Swiss can be inordinately proud of the regional specialities from their particular Canton. (Regional variations in cuisine are a good topic of conversation over a meal.)
Alcohol will usually be offered at lunch and dinner but many Swiss will refrain from drinking at lunch time. It is probably best to take your lead from your host. You may be surprised by the quality and variety of Swiss wine which are not really heavily exported and therefore little known internationally but are very good. Local wine is another good topic for the lunch table.
It is quite usual to tip in Switzerland. People very often round up to the nearest 10 CHF. As a rule of thumb, a tip of around 5% – 10% should be fine.