Sounds like it will be you first foreign posting? I dont have specific experience of Geneva, but I dont think 4000chf is not an enormous budget, particularly for a house, around Geneva. At that level you will be trading off space for cachet in a big way.

The first rule of looking for rental property is look, look and look. Most stuff is overpriced rubbish, and thoroughly depressing.

The second rule is, sadly, be prepared to make some compromises, or to spend more.

The third rule is, once you see somewhere that fits the bill mostly, go for it without wasting anymore time.

Good luck
Daniel