Lululemon sues Costco, alleging the discount retailer copied its designs

Lululemon is suing Costco, accusing the discount retailer of selling "confusingly similar" replicas of its jackets, sweatshirts and pants.

In a lawsuit filed Friday in the U.S. District Court for the Central District of California, the athletic and lifestyle apparel company claims that certain Costco products imitate its own designs so closely that it constitutes "trade dress" infringement, which occurs when a product mimics another so closely that it confuses consumers.

The apparel company claims that Costco's "knockoff" designs, or product "dupes," violate trademark law because "some customers incorrectly believe these infringing products are authentic Lululemon apparel." In other cases, "customers specifically purchase the infringing products because they are difficult to distinguish from authentic Lululemon products," the lawsuit alleges.

"Indeed, one of the purposes of selling 'dupes' is to confuse consumers at the point-of-sale and/or observers post-sale into believing that the 'dupes' are Plaintiffs' authentic products when they are not," the lawsuit alleges.

Lululemon refers to itself in the lawsuit as a "path-breaking" apparel company that has set a new standard for performance athletic wear, adding that its "construction techniques" and "strategic fits" help it stand out to consumers. Reached for comment, the Vancouver, Canada-based company said it fiercely defends its products.

"As an innovation-led company that invests significantly in the research, development and design of our products, we take the responsibility of protecting and enforcing our intellectual property rights very seriously and pursue the appropriate legal action when necessary," a Lululemon company spokesperson told CBS MoneyWatch.

Costco did not immediately respond to CBS MoneyWatch's request for comment.

While copycat products can be so poorly constructed and designed that they pose no threat to the originals, Costco's dupes have caused a stir for their verisimilitude to the authentic Lululemon goods. A January headline in The Washington Post read, "Is that hoodie Lululemon or a Costco dupe? No one has to know but you." On social media, users post images and videos of Costco athletic-wear products with the hashtag #luludupe or #lululemondupes.

The items at the center of the lawsuit include Lululemon's popular "Scuba" hoodies and sweatshirts, its "Define" jackets, and "ABC" stretch pants — that resemble khakis pants — for men.

Lululemon's Scuba hoodie retails for $118, while its Define jacket sells for $128. The ABC pants cost $128.

According to Lululemon, Costco's infringing products include:

• Danskin Ladies Half-Zip Hoodie
• Danskin Half-Zip Pullover
• Jockey Ladies Yoga Jacket
• Spyder Women's Yoga Jacket
• Hi-Tec Men's Scuba Full Zip
• Kirkland 5 Pocket Performance Pant

Lululemon is seeking damages in the form of lost profits, and for Costco to cease the manufacturing and distribution of products Lululemon claims violate trade dress.