Last year in the United States some very large companies paid some very large fines for export control and sanction violations. In June 2012 United Technologies Corporation agreed to a $78 million settlement with the U.S. Department of State and the U.S. Department of Justice for illegal software exports to China, and Dutch bank ING paid $619 million to New York city and state governments and the federal government to settle allegations of breaches of sanctions against Cuba and Iran. Two months later, Standard Chartered Bank made a $340 million settlement with the New York Department of Financial Services (DFS).

While the U.S. has a long history of sanction-related enforcement, the European Union’s efforts have been less high-profile, and without the big-ticket fines and settlements. But the European Union has become increasingly robust in its use of unilateral sanctions—meaning restrictive measures that go above and beyond those imposed by the United Nations Security Council. The newly imposed sanctions, spurred by Iran’s race to attain nuclear power, affect European businesses across a wide spectrum of industries, including exporting companies, banks, insurance companies, and shipping companies.

For law firms, this new emphasis creates an opportunity to build on existing skill sets, including E.U. law and customs and trade, and gives firms the chance to court new clients. “[Since the tightening of the sanctions regime] we’ve been inundated with new requests from clients,” says Charles Claypoole, a senior associate at the London office of Latham & Watkins. “E.U. and non–E.U. companies are asking us what European sanctions mean for the way they do business.”

The E.U.’s tougher stance sprang from new legislation passed in June 2010 that imposed restrictive measures on trade, supply of financial services, and transactions in the energy and transport sectors on Iranian entities. But the limitations on doing business with certain other countries such as Syria and Libya have also become stronger in the last few years. This is in part because there is now political consensus among E.U. member countries about current key foreign policy problems, including the need to stop Iran from developing nuclear weapons. “Recent experience has shown the E.U. that sanctions can be effective in achieving such foreign policy goals,” says James Killick, a litigation partner in the Brussels office of White & Case.

U.S. firms like Latham, White & Case, and Steptoe & Johnson are drawing on the experience of colleagues in Washington, D.C., and New York. Other firms, such as Baker & McKenzie and Bird & Bird, which have experience in working with E.U. and member state regulatory authorities such as the Export Control Organization (ECO), are also benefiting from the new sanctions-related focus. But there are key differences between the European approach to enforcement and that of the United States. European Union authorities usually do not have the resources to pursue investigations culminating in the kinds of fines and administrative actions such as the ones imposed by the U.S. Department of the Treasury or the U.S. Department of Commerce’s Bureau of Industry and Security. Furthermore, European companies don’t have the same culture of self-reporting and voluntary disclosure as their U.S. counterparts.

However, that doesn’t mean that companies that operate in the E.U. are taking the new regulations lightly, says Baerbel Sachs, a partner in the Berlin office of Noerr. “Before July 2010, our clients were typically multinational companies, but since then we’ve been advising smaller and medium-sized companies that would never have imagined needing sanctions advice three years ago,” she says.

Sachs say that clients typically ask her and other Noerr attorneys to advise them on a wide range of issues, including whether existing business relationships are potentially noncompliant with sanctions or how to proceed with transactions without being in breach of the regulations.

Lawyers are also now advising non–E.U. purchasers of E.U. companies about whether they’re likely to inadvertently inherit sanctions-related exposure after an acquisition. “It’s now become a standard part of M&A due diligence,” says Latham’s Claypoole.

Recent suits such as the 2011 dispute between Arash Shipping Enterprises Company LTD and Groupama Transport illustrate the problems that newly imposed sanctions can create on existing business contracts. Arash, a Cypress-based company that is controlled by an Iranian company, was one of a number of coinsureds under a composite policy issued by marine and transport insurer Groupama that covered a fleet of oil tankers. When the E.U. imposed sanctions against Iran, Groupama canceled the policy. Arash filed suit in the High Court in England and Wales, but the court ruled that Groupama was justified in canceling the policy.

These kinds of suits are expected to increase, says Jochen Beck, a Squire Sanders associate in the firm’s Brussels office. Sanctions practice is “just about where competition law was 15 years ago—on the cusp of really taking off.”