Paraphrase this.
The Parties shall take all reasonable steps to ensure that the U.S. Treasury Department and any relevant Member State promptly inform one another, and consult with one another and the Parties, if necessary, where they consider that personal data have been processed in breach of this Agreement.
As soon as it considers personal data had been processed in breach of this Agreement, the Parties shall take all appropriate steps to ensure the United States Treasure Department and the Member State concerned immediately inform each other, enter into consultations, including, where appropriate, the Parties.