Patrick Pouyanne, Chairman and CEO of French energy company Total visits the Shetland Gas Plant on May 16, 2016, in the Shetland Islands.

French oil giant is expected to sign a deal Tuesday with to develop the country's largest natural gas field, paving the way for Western oil companies' return to the Persian Gulf country.

Total would be the first European integrated oil company to sign a contract to develop Iranian oil or gas assets after the lifting of sanctions on Tehran earlier this year. The deal would also advance Iran's goal of tapping its vast oil and natural gas reserves, which are the fourth and second largest in the world, respectively.