It is possible to define user groups within the finance module that will allow certain users to have access to different levels of company transactions.  Per below you can see 5 different user groups (defined at the company level) and each has the ability to perform different levels of transactions.

If by entity, you mean by Company or by Site, then no, there is no out of the box method for this.

There are some other posts on this subject though where there are clever customizations possible to handle this.

Thanks!! 

And do you know if there is a possibility to restrict the visibility of the data itself. 

My understanding is that the restrictions relate more to access to modify rather than has accesses to the data itself. 

Thanks again!

Giuliana 

The only way to restrict the data is by not granting access to the Company or the Site in the first instance.  That is an all or nothing switch, it is really hard to allow access to some data in a site, but not all it.