Welcome to Bern.
If you will be working at the University of Bern, getting in touch with the students association of the university might help.
(In German) http://subnew.unibe.ch/de/Dienstleistungen/Wohnen
Perhaps a better option is to contact the international office. They will know about temporary accommodation options for newly arrived academics
This is their page (also in German) with a list of options. http://www.int.unibe.ch/content/welc...index_ger.html
On the right side of the page are bunch of websites for apartment rental in Switzerland. But these are hard to get from abroad due to the need for various documents in the application available only after starting to reside here. Would try those only after arriving here.