According to Kokoro & Moi:
The Helsinki City Executive Office is a department subordinate to the City Board. It functions as a planning, preparation and executive body for the City Council, City Board and the Mayors.
Kokoro & Moi was selected to re-design and update the identity for the office, including various communications materials from publication concepts to presentations and from digital applications to stationery. New visual identity was based on the use of the existing elements of the identity in new fresher and more attractive ways. In addition to defining the use of colors, photography, illustrations and the coat-of-arms, we introduced a new element to the whole: Helsinki Avoin Sans (avoin = open), a bespoke open-source typeface. This new humanist and legible sans-serif typeface became a corner stone for the updated identity system.
Helsinki Avoin Sans can be freely used and shared under the Apache licence and there is versions for all the needed use from web to office and other applications.
Since introducing Helsinki Avoin Sans to the Helsinki City Executive Office, the font has been widely welcomed by other city departments and services as well, and used for various communications needs of the City of Helsinki.
You can see the font in use on the Digital Helsinki website (itself open source).