If used in good faith an earlier used sign which is identical to a mark can be a due cause

TRADE MARK LAW

‘Due cause’ may also relate tot the subjective interest of a third party using a sign which is identical or similar to the mark with a reputation.

"45. It follows that the concept of ‘due cause’ may not only include objectively overriding reasons but may also relate to the subjective interests of a third party using a sign which is identical or similar to the mark with a reputation."

‘Due cause’ is intended is intended to strike a balance between the interest in question, not to resolve a conflict between a mark with reputation and a similar sign.

"46. Thus, the concept of ‘due cause’ is intended, not to resolve a conflict between a mark with a reputation and a similar sign which was being used before that trade mark was filed or to restrict the rights which the proprietor of that mark is recognised as having, but to strike a balance between the interests in question by taking account, in the specific context of Article 5(2) of Directive 89/104 and in the light of the enhanced protection enjoyed by that mark, of the interests of the third party using that sign. In so doing, the claim by a third party that there is due cause for using a sign which is similar to a mark with a reputation cannot lead to the recognition, for the benefit of that third party, of the rights connected with a registered mark, but rather obliges the proprietor of the mark with a reputation to tolerate the use of the similar sign."

Earlier use of a sign similar to a mark in relation to a product which is identical to that for which that mark was registered can be considered as due cause, if  it is used in good faith.

"61. [...] the proprietor of a trade mark with a reputation may be obliged, pursuant to the concept of ‘due cause’ within the meaning of that provision, to tolerate the use by a third party of a sign similar to that mark in relation to a product which is identical to that for which that mark was registered, if it is demonstrated that that sign was being used before that mark was filed and that the use of that sign in relation to the identical product is in good faith. In order to determine whether that is so, the national court must take account, in particular, of:
– how that sign has been accepted by, and what its reputation is with, the relevant public;
– the degree of proximity between the goods and services for which that sign was originally used and the product for which the mark with a reputation was registered; and
– the economic and commercial significance of the use for that product of the sign which is similar to that mark."

IPPT20140206, CJEU, Bulldog v Redbull

C‑65/12 - ECLI:EU:C:2014:49