A "R in a circle" (®) symbolizes that a trademark can be used as a registered trademark is registered. The use of the ® symbol is legally protected and can only be used for trademarks that are actually registered in the respective country or territory for the relevant goods or services.
Placing an R in a circle on a trademark that is not registered or not registered in this way is unfair competition. Fame of property rights. It can be warned and prosecuted as misleading under competition law.