A person says that the sentence "this is the place where I recommend to you" isn't correct but "this is the place which I recommend to you" is correct.
Is this right?
Yes, that person is right. The first sentence might be fixed this way, if we wanted to retain 'where':
I googled around, and the matter seems to be with the grammatical role of "where". In your example, it seems to work as an adverb.
The word "which" works as a relative pronoun referring to "the place".
P.S. "Where" is classified as part of the so-called "WH-adverbs":
P.S. I was advised to change my answer, because the verb "recommend" has some nuances of usage:
Maybe a native speaker will post an add-on answer explaining the best way to use 'recommend' in your sentence.
It may be better to just omit the "which" since it is unnecessary so your sentence remains simpler:
This is the place I recommend to you.