Public relations companies

Publicis Groupe S.A. is a French multinational advertising and public relations company. As of 2024, the company is the largest advertising company in the world by revenue. Based in Paris, it is one of the 'Big Three' advertising companies, alongside WPP and Omnicom. Publicis Groupe S.A. is headed by Arthur Sadoun, and its agencies provide digital and traditional advertising, media services and marketing services to national and multinational clients.

Steorn Ltd () was a small, private technology development company based in Dublin, Ireland. In August 2006, it announced that it had developed a technology to provide "free, clean, and constant energy" via an apparent perpetual motion machine, something which is contrary to the law of conservation of energy, a fundamental principle of physics.