Internal references to pages like, for example, the legal notice, data protection, contact information etc. should not be marked as “nofollow” for the purpose of the “natural PageRank flow” of your domain.
Generally there is no advantage in adding the nofollow attribute to internal links. (Please also see: “When does it make sense to use NOFOLLOW on internal or external links?“).
In case you are contemplating using “nofollow” on a page like the legal notice, because this page is ranked higher than your desired target page on the search engine results pages for a specific/important keyword, it is recommended to simply use less internal links to the legal notice, instead. You could just link to it once from the start page, instead of having a side-wide link within the footer – for example.
If it is too much work to “recreate” your internal link or if some other reason makes this impossible, a good alternative would be to use the meta robots values NOINDEX, FOLLOW on the target page.
In our example scenario, the value of the robots-attribute should be set as follows on the target page (in this case legal notice):
Due to this markup in the source code, the page itself will not be included in the index, but all links on it will be crawled:
<meta name="robots" content="noindex, follow">
