Rinse couscous under cold water until water runs clear.
In a saucepan, over medium heat, bring the broth to a boil. Add couscous and cook according to the directions on the package.
In the meantime, heat the oil in a sauté pan over medium heat. Sauté the carrot until it starts to soften for approximately 5-7 minutes. Add in the red onion, spinach, and lemon juice; cook until the spinach is wilted. Toss in the couscous. Season with salt and pepper to taste before serving.