Short answer
In Europe, a scent formula or signature scent cannot easily be monopolised through copyright or a scent mark. The greatest practical protection usually lies in contracts, confidentiality, exclusivity with the perfumer, brand name, packaging and other classic intellectual property rights.
Why copyright is difficult
For copyright protection, a work must be sufficiently precise and objectively identifiable. In the Levola Hengelo case, the Court of Justice of the European Union ruled that the taste of a food product could not be identified with sufficient precision and objectivity to qualify as a copyright work.
That case was about taste, not perfume. Still, the reasoning makes it clear why protecting a scent as such is legally complicated: scent perception is variable and difficult to define objectively.
And a scent as a trademark?
That too is very difficult in practice at EU level. The current EUIPO guidelines state that olfactory and taste marks are currently not acceptable because, with current technology, they cannot be represented in the register in a sufficiently clear, precise, durable and objective way.
Historical case law such as Sieckmann also showed that a chemical formula, scent sample or mere verbal description does not easily solve that problem.
What can you protect?
A company can protect several layers around a signature scent.
Contractual exclusivity: agree with the perfumer or supplier for which area, which sector and which period the formula is exclusive.
Confidentiality: the exact formula can be treated as a trade secret when appropriate measures are taken to keep the information confidential.
Trademark protection: the name of the scent concept, the company name and visual signs can be registered as a trademark under certain conditions.
Design and packaging: the bottle, packaging or other visual elements can enjoy separate protection when the conditions are met.
Exclusive is not the same as a legal monopoly
A supplier can contractually promise not to sell a formula to competitors. That is something different from an absolute intellectual property right against everyone.
For companies investing in their own signature scent, it is therefore important to lay down agreements on ownership, use, access to the formula, exclusivity and termination contractually in advance.
Legal advice remains project-specific
The exact protection depends on contracts, jurisdiction and the way the scent is developed and used. For a valuable custom formula, specialised IP advice is recommended.