Territorially, the condition as to reputation must be considered to be fulfilled when the EU trade mark has a reputation in a substantial part of the territory of the European Union. In certain cases, the territory of a single Member State may be considered to constitute a substantial part of that territory.

In examining this condition, it is necessary to take into consideration all the relevant facts of the case, in particular the market share held by the trade mark, the intensity, geographical extent and duration of its use, and the size of the investment made by the undertaking in promoting it.

In order to enjoy the protection provided for in Article 8(5) of Regulation No 207/2009 on the European Union trade mark, a registered trade mark must be known by a significant part of the public concerned by the products or services which it covers.

The question of whether there is due cause which makes it possible to use a mark which adversely affects a mark with a reputation is a matter which must be interpreted restrictively.

Nevertheless, it must be recalled that the purpose of Regulation No 207/2009 on the European Union trade mark is generally to strike a balance between the interest which the proprietor of a trade mark has in safeguarding the functions inherent in that mark, on the one hand, and the interests of other economic operators in having signs capable of denoting their products and services, on the other.

In the system for the protection of marks introduced by Regulation No 207/2009, the interests of a third party in using, in the course of trade, a sign identical or similar to an earlier mark with a reputation and in having it registered as an EU trade mark must inter alia be considered, in the context of Article 8(5) of that regulation, in the light of the possibility for the user of the mark applied for to claim ‘due cause’.

It follows that the concept of ‘due cause’ should not be interpreted as being limited to objectively overriding reasons, but may also relate to the subjective interests of a third party already using a sign which is identical or similar to the earlier mark with a reputation and wishing to register it as an EU trade mark.

That is why the Court has held that the proprietor of a trade mark could be obliged, pursuant to the concept of ‘due cause’, to tolerate the use by a third party of a sign similar to that mark, including in relation to a product or service identical to that for which that mark was registered, provided that, first, it had been demonstrated that that sign had been used before that mark was filed and, second, that the use of that sign had been in good faith.

The Court has stated that, in order to assess, in particular, whether the third party in question had used the sign similar to the mark with a reputation in good faith, it was appropriate to take into account, inter alia, (i) how that sign was accepted by, and what its reputation was with, the relevant public, (ii) the degree of proximity between the goods and services for which that sign had originally been used and the goods and services for which the mark with a reputation had been registered, (iii) when that sign was first used for a product identical to that for which that mark was registered, and when that mark acquired its reputation and, (iv) the economic and commercial significance of the use for that product of the sign which was similar to that mark.

(see paras 52-57)