Émigrés were typically traditional military leaders, so they had experience with the army and could possibly have encouraged internal revolt with members of the French army. However, because there was only a small number of émigrés, the effect these military leaders had was limited. It did give émigrés the opportunity to strike back at France and restore the monarchy. Louis XIV’s brother (Louis XVIII) set up court in Koblenz, Germany with other émigrés. A member of the court, Louis-Joseph, decided to lead an army in hope to restore the Monarchy and regain access to France. This resulted in a defeat in Quiberon Bay, Southern Brittany, where approximately 600 émigrés were executed. On top of this, émigrés were wealthy but they would not have been able to afford to run a war for very long as this costs large amounts of money.
Another threat émigrés created was the fact that they had close connections with monarchies across Europe. This fact could have triggered foreign intervention which would have caused a major set-back in the French Revolution: this would have caused a return of the Monarchy. External enemies could have worked out a plan with Louis XVI, who was an internal enemy of the Revolution. Royalists and Monarchists would have gladly supported Louis.
Austria and Prussia were also