The labor peace agreement shall be a written agreement enforceable between the employer and the labor organization under § 301(a) of the Labor Management Relations Act of 1947, 29 U.S.C. § 185(a). The labor peace agreement shall contain, at a minimum, a provision prohibiting the labor organization and its members from engaging in any picketing, work stoppage, boycott, or other economic interference with any of the employer’s operations in which the City has a proprietary interest, for the duration of that interest. Ord. 07-578