Oiled parquet is maintained quite differently than waxed or sealed parquet. Therefore, there cannot be a single instruction on how to care for "parquet." A distinction must be made between sealed, waxed, or oiled.
If I want to know through Google how to care for oiled parquet, I probably don't enter hard oil, but care parquet
Then comes:
Oiled parquet should be re-treated two to three times a year with a special care oil.
On a website that sells nothing, as far as I can see (zuhause.de powered by T-Online). Retreatment implies that you have to get to it, so take everything out, care oil, let it soak in, put everything back.
And then there is also something about "shoes off," in other words: completely unsuitable for somewhat heavier use (private entrance area).