Well-known trade mark status is commonly granted to famous international trade marks in less-developed legal jurisdictions.
Pursuant to Article 6 bis of the Paris Convention, countries are empowered to grant this status to marks that the relevant authority considers are ‘well known’. In addition to the standard grounds for trade mark infringement (same/similar mark applied same/similar goods or services, and a likelihood of confusion), if the mark is deemed well known it is an infringement to apply the same or a similar mark to dissimilar goods/services where there is confusion, including where it takes unfair advantage of the well-known mark or causing detriment to it.
Furthermore, a well-known trade mark does not have to be registered in the jurisdiction in order to bring a trade mark infringement action (equivalent to bringing a passing off claim without having to show goodwill and having a lesser burden of proof).
It is therefore easier to use the well-known mark to oppose the use of other trade marks and to show infringement.