Swisscom and Lausanne Industrial Services (SiL) have agreed to jointly create a FTTH network in the Swiss city.
The two companies signed a declaration of intent in September 2009 but have now concluded a firm cooperation agreement.
The partnership covers the "last mile" between local exchanges or distribution points and individual buildings, as well as interior cabling.
A new company will be established to implement and manage this network, which aims to connect all the buildings in Lausanne to a high-speed fibre-optic network by the end of 2017.
Swisscom will transfer 50 percent of the ownership of the network it builds to this company within five years.
The operator will retain full ownership of the network in the districts of Bergières, Chalet-à-Gobet, Maladière and Sallaz.
However, both parties will grant each other indefeasible right of use (IRU) of the cables for a minimum period of 70 years in the districts they do not own.
SiL is a public body that provides services including electricity, gas and multimedia; it owns Citycable, a triple-play provider.
Swisscom said it aims to roll out fibre to a third of Swiss households by the end of 2015.