Once you reach your GCSE choices, languages (apart from English which is a core subject) become optional, so if you have not enjoyed your time trying to learn French or German or any other language the school enabled you to experience, you can say goodbye to them for year 10.
However, if you found them more enjoyable, like the challenge of a new language, and want to be able to holiday abroad and have some chance of understanding what is being said, then you may want to consider continuing with French. As well as advancing with the French you have learnt in early school years, you will now need to get more technical with tenses and rules, and part of the examination process is an oral exam which is recorded onto tape and sent to the moderators for marking.
Being on a GCSE language course can be very exciting as you may get the opportunity to go on an exchange and spend some time with a French family who have a child your age studying English, giving you the chance to practice in a real environment. You will then have the child stay at your house for a while so they can practice their English. Other schools prefer just to take a group of you to a hostel in France for a week, and go out as a class. However, the exchange is better as you stay and interact with French people, probably learning more.