Bromates can be removed with reverse osmosis filtration or maybe activated charcoal - not sure how much charcoal would be needed. So while yes filtration works, pretty sure most kitchen filter cartridges are not using reverse osmosis - but might have activated charcoal.

As an aside
If both sides use desalination, then the raw sea water used by both sides would contain the same mount of bromides. Bromates are created from bromides.

Bromate creation would be dependent on how the water is processed - testing would be required to determine how much is created.

At least the Fr side came out with numbers, the Dutch side said all is good - I would prefer the Dutch side also came out with numbers so we could see for ourselves

J&B