It was a law?
Oh, and regarding this add-on subject of Slavery Remembance Day in the BBC story:
"France has set an example by being the first country in the world - and still the only one today - to recognise slavery as a crime against humanity. I have decided to establish a day of remembrance in France."Maybe they should have two remembrance days - one to remember they abolished it in 1794 and another to remember they had to abolish it again in 1848.