The German government is hearing Fiat’s plans to take control of Opel and create a European car-making giant.Fiat’s CEO Sergio Marchionne says he has a month to convince Berlin to give its blessing to what he calls a “marriage made in heaven.” On the other side of the table is German Economy Minister Karl-Theodor zu Guttenberg. He has already insisted that any investor in Opel would have to ensure German plants remain open. Zu Guttenberg is joined by Foreign Minister Frank Walter Steinmeier. Meanwhile, German union leaders have voiced concerns over the Fiat proposals. A spokesman for the IG Metall union said he wanted assurances for employees that include guaranteeing a certain volume for each factory and keeping production sites and jobs. Fiat claims any car-maker must make more than 5.5 million models a year to stay afloat. It says a deal with Opel would allow the resulting company to reach this target. Opel is currently part of General Motors, which faces the threat of bankruptcy along with its domestic American rival Chrysler. Fiat signed a partnership deal with Chrysler last week. A Fiat-Opel-Chrysler alliance would generate an estimated 80 billion euros a year in revenue.