Wis. Stat. § 428.209: Exclusive state regulation authority.

The state shall have sole authority, except as provided under federal law, to regulate any matter governed by this subchapter or by a rule promulgated under this subchapter. No local governmental unit may attempt to regulate, directly or indirectly, any matter governed by this subchapter or by a rule promulgated under this subchapter, including enacting an ordinance or adopting a resolution or imposing reporting requirements.