MEGA Brands, makers of Mega Bloks, filed suit on Friday against Lego Juris A/S and Lego Group, seeking to invalidate a 1999 trademark. This after U.S. Customs and Border Protection advised the company that it intended to restrict importation of Mega Bloks, which MEGA Brands has sold in the United States for 20 years. MEGA Brands is also seeking a restraining order and preliminary injunction.

The issue seems to be whether Lego’s trademark is primarily functional in nature. That is, whether the shape of the product enjoys trademark protection even though it also serves a functional purpose and the patents for Legos are expired.

[1/24/2012] Update: After receiving reassurances from U.S. Customs and Border Protection, MEGA Brands has dropped its suit.