De beschikking blijft staan, tenzij de gemeente die herziet.

Blijven staan is an idiomatic expression here. In legal or administrative Dutch, it means something like to remain in place, to remain valid, or to stand.

So De beschikking blijft staan does not mean the decision is literally standing somewhere. It means the decision remains as it is and continues to be valid.

English has a similar idea in phrases like the decision stands.

Tenzij means unless.

It introduces a subordinate clause, and in Dutch subordinate clauses, the conjugated verb usually goes to the end.

So:

• main clause: De beschikking blijft staan
• subordinate clause: tenzij de gemeente die herziet

That final herziet is there because tenzij triggers subordinate clause word order.

Die refers back to de beschikking.

So the structure is:

• de beschikking = the decision/order/ruling
• die = that one / it

In other words, tenzij de gemeente die herziet means unless the municipality revises it.

Because beschikking is a de-word: de beschikking.

When Dutch refers back to a de-word with a demonstrative pronoun, it often uses die.

• de beschikking → die
• het besluit → dat

So die matches the grammatical gender of beschikking.

Also, for things rather than people, Dutch often prefers die/dat over personal pronouns like haar/het in this kind of formal sentence.

No. Here die is not a relative pronoun. It is a pronoun standing in for de beschikking.

A relative clause would look more like:

• de beschikking die de gemeente herziet

That would mean the decision that the municipality is revising.

But your sentence is different:

• De beschikking blijft staan, tenzij de gemeente die herziet.

Here die is simply the object of herziet and means it or that decision.

Herziet is the third-person singular present tense of herzien, which means to revise, to review, or to reconsider.

So:

• de gemeente herziet = the municipality revises

A useful thing to notice: herzien is not separable here. So you do not split it into something like ziet ... her.

Compare:

• infinitive: herzien
• present: herziet
• past: herzag

It is also a fairly formal verb, especially in official or legal language.

Because de gemeente means the municipality as one institution or body, so Dutch treats it as singular.

That is why the verb is:

• de gemeente herziet
  not
• de gemeente herzien

This is similar to English using singular in the municipality revises it.

Yes, very much so.

Words and phrases like these are common in official Dutch:

• beschikking
• blijft staan
• herzien

A more everyday version might use simpler wording, but this sentence sounds natural in administrative, legal, or municipal communication.

So if you saw this in a letter from a local authority, it would sound completely normal.

Yes, the meaning would be very close:

• tenzij de gemeente die herziet
• als de gemeente die niet herziet

But tenzij is the more natural and compact way to say unless.

It is especially common in formal writing, where Dutch often prefers concise wording.

Because the sentence directly names who does the action: de gemeente.

So the active version is simpler:

• tenzij de gemeente die herziet = unless the municipality revises it

A passive version would also be possible, but it would be heavier:

• tenzij die door de gemeente wordt herzien

That sounds more formal and less smooth here. Dutch often prefers the active when the agent is known and stated.