The first prerequisite for trademark capacity is that the trademark application is a sign. The mere possibility of being a sign in relation to any goods or services is sufficient.
If, for example, an abstract colour is applied for, it cannot generally be assumed that a colour as such is a sign. Usually, a colour is a mere characteristic of objects. However, it can be a sign. This depends on the context in which the colour is used. In principle, however, a colour as such can be a sign in relation to a product.^[1] The shape of a product can also be a sign in principle.^[2] In contrast, a general and abstract application for all conceivable shapes of a transparent collection container of a hoover is not a sign due to a lack of concretisation. Such an application is in reality exhausted in a mere characteristic of the goods concerned.^[3] Not comparable with this - contrary to the case law of the Federal Court of Justice^[4] - is the case of a variable sign which, with an exact description, that covers several (always violet-coloured) sign variants but which can nevertheless be traced back by the public to a possibly origin-indicating core sign:

this can be a sign; at most, it lacks distinctive character.
Which sign is actually involved is also determined by the indication of the trade mark categories. A figurative mark may be assessed differently from a colour mark.^[5] It is therefore not possible to switch between different categories - for example, from figurative mark to colour mark or from position mark to shape mark.^[6] If there is a discrepancy between the representation of the trade mark and the indication of the category, the trade mark cannot be registered.^[7]