In France, every resident is supposed to file a tax return, even if you have no income whatsoever. In general, you want to do that because the paper you will get (avis de non-imposition) is often required to get various benefits and can be used to be exempted from property taxes or TV license (if you are in fact eligible for these exemptions, which may not be your case).
At the same time, if your income is too low to incur income taxes, not filing or filing late won't have any serious consequences. Penalties are always computed as a percentage of the taxes due (no lump sump or fixed fines). If you don't owe any tax, there is no penalty.
On the Swiss side, some taxes are likely to be withheld and I am not sure what your obligations may be. If the compensation was high enough to trigger income taxes in both countries, you would have to look up tax agreements between France and Switzerland (exact rules depend on the canton) to make sure it is processed properly.