In my limited experience, painless. I'm Canadian, and I've been to Switzerland twice: first as a tourist, then on a work visa. Both times I entered the Schengen area via Charles de Gaulle, then flew to Geneva or Zurich respectively.
Both times my passport was checked in Paris... just a "what's the purpose of your visit", a look at the passport and visa, and a wave through. In Geneva, there was no border control (just a "go this way if you have anything to declare" or "go this way to the street" fork). In Zurich, there was another border guard; same deal as in Paris.
Both times my passport was checked in Paris... just a "what's the purpose of your visit", a look at the passport and visa, and a wave through. In Geneva, there was no border control (just a "go this way if you have anything to declare" or "go this way to the street" fork). In Zurich, there was another border guard; same deal as in Paris.