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.