This study is an example of a lesson plan based on project-based teaching of a subject in French class. Among the learning methods, the project-based learning approach is one of the most suitable for achieving the goals set in foreign language lessons. This application example includes an example lesson plan application based on the project learning prepared for a real-life performance task (writing a petition) and the learning of petition writing of students learning French as a foreign language within the framework of project-based learning approach. The example of a form is also given in the study in order to evaluate students’ products and performances in a versatile way.In the study, the students have similarly demonstrated the correct petition writing performance through a properly and correctly written sample petition, thanks to the lesson plan that explains each step in detail. The student, who is active at all stages of the learning process, has the opportunity to evaluate her performance with the Self-Assessment form and Rubric. In foreign language learning, project-based learning that provides the students with cognitive process skills has become a very appropriate approach in terms of learning and acquiring language, using it effectively in problem solving and communicating by associating it with daily life. The student, who is at the center of the learning process at all stages, acquires more permanent and meaningful learning as she performs the learning process herself, and thus improving herself as a lifelong learner.