I just checked what we were told 3 years ago when we went to sign our contract (it was Regie Naef - a serious regie) and we had to pay the first month + frais de dossier there, although they also accepted Postcard and Maestro (but no bank transfer). So this seems to be "common" (although I don't understand why...).

As far as I know Regie du Centre is quite serious. Obviously they will have to give you a receipt for what you pay...

Thank you all for the advice!

i rang Cagi (asloca were closed today) and they said this is common practise here and that the regie is reputable. I just thought that it was weird to ask for cash, I feel a bit more reassured now. 

Im going to use swiss caution for the deposit too, the regie is actually going to look after that for me too.

Thanks again and have a lovely evening!

Be careful, Katherine.  I have never been asked for any "cash" for the first month's rent.  It was always a bank transer AFTER the "Bail a Loyer" was all signed off. So it sounds dodgy to me (but Geneve is different to Lausanne I guess).

I used to think Swiss Caution were fab and recommended to everyone - but it seems that the banks are now offering a similar (free) service, without having to pay the CHF 230 a year for the "insurance".   But check out the small print.

I thought the SC advantage would be when I moved out, but the Regie (Naef BTW) are taking forever to sort it and SC are not being very helpful.  3 months after moving out, SC have still not terminated my contract and are ignoring my emails (yes, written in French) and not refunding my 2013 "insurance" which should have ended in March.

Unfortunately, when it comes to both Regie and SC (or anything to do with renting it seems) - to use an English expression - if they're offering you an apartment, then they "have you by the balls". 

Bastards, the whole lot of them! Good luck - and again and again - READ THE SMALL PRINT!!! (However small!)