Firstly, ask ASLOCA for the definitive answer.

Put up some adverts, unless the house is unuseable or very over-expensive, you will always find someone.

I doubt that your work transfer has any legal standing in the affair.

Another point, ask the landlord, he may not be interested in you finding someone anyway, or prefer to find a tennant himself (that way it is easier to increase the rent)..

When I went to ASLOCA they told me that all I had to do is to present a dossier of someone who is "viable", and that's it. My advice is go and get their expert advice. If you are not a member you can pay right there. It is well worth it. You speak to a lawyer then and there, and they will guide you. 

In Switzerland, especially in this changing market, owners will hold you to the letter of your lease. You have to provide a 'solvable' and viable candidate who is willing to sign.... If they back out at the last minute, in the end, you haven't provided anyone and you're still responsible for the lease. It's very black and white.

If you present someone solvable and the owner rejects them, then you've satisfied your part and you would be out of your lease.

Transferring to France won't help your case unless you specifically have a 'diplomatic clause' stipulating if you get transferred out of CH, you could give (generally) 3 months notice. It sounds like you don't have this.

Like the other posts, I would highly recommend going to ASLOCA to get their advice. If you've been in your flat for a year or more, you're most likely over paying your rent and ASLOCA will help presenting a case to the owner to adjust the rent to the market, which will help you to find a replacement. I have a friend who recently did this and the owner refused to adjust the price (they couldn't find anyone for the price they'd been paying the last 4 years), in which case the owner released them from the lease despite not having found a replacement in hopes of getting the rental amount he wanted. With a little help from ASLOCA, you should get this solved in less than 2 weeks.

In the meantime, I would continue to advertise the place (Anibis, petitesannonces.ch, glocals, etc...) until you find someone or the situation is resolved. The last thing you want is to leave the country having to pay a second rent for the next year.

http://www.asloca.ch/questions-r%C3%A9ponses-faq

Interesting FAQ section on the website of ASLOCA. Apparently it is sufficient to present only one candidate.

Good luck! :)

Ok so we've been to see asloca who said that we should have requested the rent decrease in April when the notice was due as it won't take effect now until August 2014. Matthew could you give me more info on what your friend did as ASLoCA seem to think we have absolutely no way out!

I saw that the tauz hupothecaire has gone down since took lease. In lease it says 2.75% but the rate has been at 2.25 and since 2 days its gone down to 2%. Surely there must be something we can do?

According to rules related to "How to proceed using taux hypothecaire and ask for a rental reduction " you can write a registered letter and kindly suggest you wish  a 3% rebate on your monthly rental due to Tx  Hypothecaire decrease. This is public info which on on Air yesterday.

You have to look for another solvable tenant who wishes to sign the contract as is and you are out. If the owner refuses the tenant for convenience reasons, you are still out. Always ask for the documents of the interested new tenant and send a letter (recommandée) to the owner with those documents.