The French revolution started because of paranoia, the people started suspecting of others being against the revolution then the Jacobins started executing people of suspicion. This led to the execution of Marie Antoinette which caused the French revolution to become more violent and extreme. That is when Robespierre starts going Psychotic a starts sentencing anybody who talks about the french revolution to the guillotine causing a death of 40,000 me & women, the arrestFrench for 300,000 men and women that when Robespierre friends of the Committee of public safety told him that he was becoming bloodthirsty ad he was killing too many people. That makes Roespierre furious and he sentenced his own friends to the guillotine. Then the National convention arrested Robespierre because he was accused of being corrupted and was later on taken to court to be judged he was sentenced to death by the Guillotine because they believed that it was the only way to end the Reign of Terror.
This challenged the old way of the monarchy by having three groups of people who control France instead of having one person rule and make all the decisions. Anybody could rule you don't have to royal blood to rule instead of being put in the Bastille, hanged, or burned you were executed by the guillotine. They went against the religion by demolishing the Christian religion entirely making a new calendar and a whole new eradication of Christianity.