I know the UN has referred to it as a Luddite measure, and some opponents of it suggest that it would reduce currency speculation, and in doing so it may reduce some of the positive currency speculation, in fact eliminating the ability for countries to operate fiscal policies inconsistent with their monetary policies, and so on.
Je sais que l'ONU assimile ça au luddisme, et certains critiques estiment que cette taxe réduirait non seulement la spéculation, mais aussi la spéculation positive et, du coup, empêcherait les pays d'adopter des politiques budgétaires contraires à leurs politiques monétaires, etc.