I'm willing to bet that if I asked my students to read the Financial Times headline, few of them would know how to say 0.1% correctly. The first problem for French speakers is that the French uses a comma ("virgule") as the decimal separator. In English we use the decimal point. Then there is the question of how to say the number '0'. Well, there are two possibilities here: "nought" or "zero". Put that all together and you get "nought (or zero) point one per cent".
Another common mistake among French speakers is to say the numbers after the decimal point in pairs. A typical error would be to say 6.34 as "six point thirty-four" rather than "six point three four". The rule is that in English you say each figure after the decimal point separately.
See this previous post for more information on saying the number "0".