CC-BY-SA. If you want other conditions, or have further questions about the terms of licence, please contact me. If you use one of my picture, I appreciate very much if you send me an email. The CC-BY-SA license is incompatible with Facebook's licensing terms. It is not allowed to upload this file to Facebook.
According to article 27 of the Copyright Act (en/de/fr/it), works installed at or on publicly accessible places or ground may be pictured, and such pictures may be offered for sale, sold, transmitted, or otherwise published. The image must not be three-dimensional and it must not be possible to use the picture for the same purpose as the original.
The works must be permanently installed, but for the purposes of the law, "permanent" means a fixed installation which may be temporary -- time limited -- but not "accidental", e.g. due to transport of the work.