A Canadian software firm filed suit in Texas federal court yesterday against Microsoft for allegedly infringing on a patent concerning document metadata, Google Watch has learned.

The firm, i4i Limited Partnership, alleges that several Microsoft products infringe on patent 5787449, "a system and method for the separate manipulation of the architecture and content of a document, particularly for data representation and transformations."

According to the complaint:

On information and belief, Microsoft, by making, using, selling, offering to sell, and/or importing in or into the United States, without authority, Word 2003, Word 2007, NET Framework, and Windows Vista, has directly or indirectly infringed (by inducement), and is continuing to infringe, directly or indirectly, the '449 Patent in this District or otherwise within the United States.

The complaint requests a jury trial and unspecified monetary damages. Representatives from i4i were not immediately available for comment.