You can recognize a traffic fine to the letter M in the upper right corner of the document called "Beschikking".
You have received this fine because you have violated the Dutch law regarding traffic regulations (Wahv). This law is concerned with traffic violations like speeding, failing to stop for a red traffic light, using a handheld mobile phone while driving or not using a seat belt while driving.
In that case, you will receive for one single contravention both a Dutch and a French language administrative decision in one envelope. You will of course only have to pay once.