The website of the French tax authorities ("Direction Générale des FInances Publiques" provides some general information in english about the French tax system, both for private individuals - residents and non residents of France - and companies.
You have access to your partiuclar secure space as soon as you get a French tax number.
Many filing formalities can or have to be made online through this webiste. It is also possible to give a power of attorney to a French tax lawyer, who will act on your behalf.
CM-Tax and its team of English speaking French tax advisors is at your disposal to assist and advise you with all tax matters in France.