Let's assume that one of your competitors has applied for a new trademark that is confusingly similar to your own: Then you, as the owner of the older trademark (which has been applied for or already registered), have the possibility to file an opposition against German trademarks and Union trademarks within three months after publication of the registration of the trademark (for the German trademark) or publication of the application (for the Union trademark). Within this period, the fee of (at least) 250 Euro to the DPMA or 320 Euro to the EUIPO must also be paid. By means of an opposition procedure, you can have the newly registered trademark cancelled in the case of German trademarks or the application for a Union trademark refused.
In addition to the official opposition proceedings, you can also file official cancellation proceedings against the registered trademark at the DPMA or the EUIPO. Depending on the circumstances, you can claim either initial invalidity or a subsequent revocation of the new trademark in these proceedings.
In addition to a cancellation due to existing older rights, a trademark can also be cancelled due to revocation grounds – namely, if after a grace period of five years of use, the trademark has not been significantly used for the registered goods and services within a period of five years. Furthermore, absolute grounds for refusal can also lead to cancellation. These grounds exist, for example, if the trademark is not eligible for protection per se (e.g. a commonly used designation for the goods or services in question) or if an applicant was acting in bad faith when filing the application, for example, if the applicant knows or ought to know that the trademark is already being used by a third party and intends to prevent this.
Further information on opposition, nullity and revocation proceedings, in particular on time limits, fees and formalities, can be found on the DPMA website as well as the EUIPO website.
If the competitor already uses their new trademark, opposition or cancellation proceedings are no equivalent substitute for asserting infringement claims.