Owner Obtaining a rental lease on property with no mortgage?

My mom owns a restaurant and the building that it occupies, there is no mortgage. Her accountant contacted her today saying the below, I have taken out her name

'It would be advisable to put in place a lease to cover a minimum period of 6
years at least (the business relief provisions). The rent payable would be a tax deduction in the company accounts but it would also be taxable income in my mother's name. I would think she could charge anything from a nominal amount up to the market rent value so it is best they agree a figure. My mother owns 100% share capital in the company.'

What is the benefit of paying a rent on a property she already owns? I don't understand the above suggestion by the accountant

She, as owner of the building is one entity, and the company is another.
The company here is whats called a close company due to the number of owners( < than 5).
The tax treatment of undistributed profits in close companies is probably, in part, whats driving this.
See here: www.revenue.ie/en/practitioner/law/notes-for-guidance/tca/part13.pdf


There are others way more knowledgeable here on the detail but the structure is very common in the SME sector and small professional practices where the individual owns the building in which the company operates.
I think it may also help if the business were to get into difficulty and make keep she and the company separate.

ps: Mods, maybe in wrong section

How much should she charge for the rent? Should she go high or low?

Am I right in saying the reason rent is being paid is to create a tax break for the company?

Thanks,