In French we are not so surprised if « une personne » resolves to be a man and if « quelqu'un » is a woman. (Feminime words like « personne » which may easily refer to a man are quite rare, currently I can just think of « sentinelle » and « ordonnance »).
Even if you try to be less obvious with masculine terms (using « on », the plural, the second person,...), the rules of French are such that the masculine will still be present. Trying to be real neutral is harder and more non natural than in English.
It is perhaps why this matter is less sensitive (at least from a man perspective, a woman one would be welcome) than in English and the common usage is to use the masculine. Doing otherwise is a political statement more often than not.
Note that while the rule le masculin l'emporte sur le féminin is often stated and used, there is a quite strong usage to use feminine name for professions mostly feminine (for example, people will use institutrice to refer to the teacher of unknown sex for small children, the use of infirmières to refer to the while profession is also common).