Two types of invalidity can be invoked: absolute invalidity and relative invalidity.
Absolute invalidity may be invoked by any third party following the violation of a general interest. It may be held against a sign, which does not meet the conditions for the validity of a trademark (illegality, lack of distinctiveness, etc.). Relative invalidity, on the other hand, may be invoked only by the owner of prior rights (trademark, name, patronymic name, copyrights), in so far as it is intented to protect particular interests only.
Examination of the chances of success, registration of the invalidity on the national trademarks’ register, enforceability against third parties: Dreyfus has perfect knowledge about the means of actions and can assist you in its implementation in order to enhance your IP rights.