This is very interesting stuff. In case I. ZR 39/08 German Bundesgerichtshof decided that deeplinkig could in some cases lead to infringement of technological protection measures. Namely, if a deep link bypassed technical measures taken by the copyright holder to ensure that its protected works could only be accessed by certain users or through certain channels (e.g. from the homepage).

For more details of this case please refer to the website of IRIS Merlin. Decision is available here.