What we are fighting against about the customs is not the idea of tax but the idea of feudality.
Complete Works, Volume 2, pages 104 to 110 (in French)
April 18th, 1847
In response to the newspaper Le National, Frédéric Bastiat explains what is the fundamental difference between the octroi (a tax levied on goods entering a city) and the tariffs. Indeed, Le National offered to support the Free-Trade association in its fight against tariffs on condition that the latter would support the former in its fight against the octroi. This type of blackmail (politicians call it bargaining) was absolutely unbearable to Frédéric Bastiat who, even if in favour of a review of the octroi, refused to accept conditions on his own battle that he believed to be just, that of free-trade.
The octroi could indeed look very similar to tariffs – it was a tax levied upon certain goods entering a city, which looks very much alike a tax levied on certain goods entering a country. However, he explains here as much as he had on January 3rd, 1847 the difference there is between a fiscal levy that aims at financing government activities and a protective levy that aims at restraining or suppressing the very exchange of the goods subject to the tax by creating a privilege for the domestic producers.
Once again, we can see that the liberal battle is not to suppress taxes in themselves but to eliminate the privileges and iniquities they produce. If liberalism is beneficial to the rich, it is not in creating privileges but in suppressing them and thus be beneficial to all, including the rich.