A class action lawsuit in the U.S. District Court of Colorado is alleging that au pairs are significantly underpaid, including in Colorado.

A Colombian au pair who worked for a Highlands Ranch family is one of five plaintiffs named in the suit. It claims that au pairs, who help families care for children and do housework, were paid an average of $4.35 an hour. That's well below state and federal minimum wage. 

Towards Justice, a Denver-based nonprofit, has brought the case on behalf of au pairs nationally.

"Our clients include a number of au pairs from both Colombia and South Africa and they request back wages and other damages," said Nina DiSalvo, the group's executive director.

Fifteen companies and non-profits selected by the federal government to administer special au pair visas are named as defendants along with the  family in Highlands Ranch. The suit also alleges violations of racketeering and consumer protection laws. The defendants are expected to contest the suit's allegations.