In your example, both versions (past and present tense in the main clause) are possible, and despite the grammatical difference, they do not differ in meaning.

If you actually wanted to express that Maria is deceased, you cannot rely on using the past tense. Based on my personal experience, I would say that most people will use the past tense here in most situations. There seems to be some driver to harmonize the temporal aspects of the relative clause and the main clause.

This applies only if the relative clause is past tense. If the relative clause is present tense, (Die Person, die du siehst), the tense difference will make a semantic difference. The sentence Die Person, die du siehst, war Maria would implicate that the person is not Maria any longer.

In your example, both versions (past and present tense in the main clause) are possible, and despite the grammatical difference, they do not differ in meaning.

If you actually wanted to express that Maria is deceased, you cannot rely on using the past tense. Based on my personal experience, I would say that most people will use the past tense here in most situations. There seems to be some driver to harmonize the temporal aspects of the relative clause and the main clause.

If one wants to pay very much attention to detail, one could argue that the past tense in the main clause introduces a slight ambiguity. You cannot expect to find this level of attention to grammatical detail in actual communication. Ultimately, the question of whether the sentence with past tense is ambiguous touches the difference between a purely grammatic and a pragmatic point of view on language. Concerning style, I would say that mixing the tenses is widely accepted. If some mathematical sense of clarity is considered a stylistic ideal, it would be advisable to use the present tense. Nonetheless, I would say that this ideal is shared amongst a small subset of speakers only, and mixing tenses is considered perfectly fine style-wise.

Everything said above applies only if the relative clause is past tense. If the relative clause is present tense, (Die Person, die du siehst), the tense difference will make a semantic difference. The sentence Die Person, die du siehst, war Maria would implicate that the person is not Maria any longer.

Both versions (past and present tense in the main clause) are possible, and despite the grammatical difference, they do not differ in meaning.

If you actually wanted to express that Maria is deceased, you cannot rely on using the past tense. Based on my personal experience, I would say that most people will use the past tense here in most situations. There seems to be some driver to harmonize the temporal aspects of the relative clause and the main clause.

In your example, both versions (past and present tense in the main clause) are possible, and despite the grammatical difference, they do not differ in meaning.

If you actually wanted to express that Maria is deceased, you cannot rely on using the past tense. Based on my personal experience, I would say that most people will use the past tense here in most situations. There seems to be some driver to harmonize the temporal aspects of the relative clause and the main clause.

This applies only if the relative clause is past tense. If the relative clause is present tense, (Die Person, die du siehst), the tense difference will make a semantic difference. The sentence Die Person, die du siehst, war Maria would implicate that the person is not Maria any longer.