The obvious changes that arrived from the French Revolution is the separation of Church and state and the decline of Church power over the minds of people, thus birthing freethinking, secularism and the rise of atheism.
For ages Europe dwelt in the dark, ruled by men who made themselves unquestionable using God as an excuse. They committed atrocities in the name of their ego and crave for monopoly. They burnt many women at the stake in the name of witchcraft hunts, ordered troops into battle fields in the name of Crusades using God as an excuse to commit atrocities. They even burnt any Christian who opposed their abuse of religious power at the stake. These martyrs burnt at the stake were the first rebels, they were Christians who opposed the use of God's name for evil. Jerome of Prague, Martin Luther and John Wycliffe shared the Idea that the Church abused it's authority and acted more human than divine.
Over time, full scale rebellion against the Church appeared in the upper class of the society, with groups like the Freemasons being notably one group of nobles and intelligent minds churning out literature that created a great awakening on the minds of the people concerning how much they had been duped by men in the name of God. Hence the rebellion started by Christians burnt for heresy had spread into wide fires of rebellion against God and not just against men using God as an excuse to commit atrocities. The populace were better educated, the anti-Church literature was in circulation around Europe.
The revolt finally the broke into chaos when weakness of the French King who was too divine in his eyes to be challenged by men thanks idea borrowed from the Church was attacked. The King was beheaded, the state was free from the clutch of men using God’s name to fill their pockets. Tumult lasted for a while, the rise of Napoleon soon took place but the spirit of the French revolution lasted and spread into Europe. People had a chance to choose between secularism and religion, and as the Bible predicts, religion declined slowly from year to year as atheism grew and is still growing till date at the expense of religion. The shape of philosophy changed, the Bible wasn't considered as the apex of truth and wisdom or a reference point which every philosopher and scientist would take readings from. Full scale rebellion against old societal concepts like the role of women arrived the scene as a result. Satanism soon kicked in the embrace of the human nature and all its selfish tendencies as its motto thanks freedom of religion.
Personally I think the French revolution has merits and demerits. The positives are that women now have a say, the Church no longer commits crime in the name of God. But the demerits is that to most individuals everything becomes permissible when the God control is deleted from their philosophical set.
To tell the truth, I don't think humanity has the ability to strike a balance between judging what is permissible and what is not. I mean, the idea is that we become our own individual supreme judge of our good and evil, thus morality is relativistic. From what I know with the human condition, we all think we are the victim of society and only few of us ever view life from the angle of us being the fragments that make up the net ill state of the human society. With almost every man playing the victim card, nobody takes up the responsibility and the presence of war amid preference for peace is the consequence. Because once we always play the victim card, we would buy the concept of attack being the best form of defense and strife would grow in society as everyone attacks and attacks. The basic ideas of Jesus is the preference of not attacking to attacking, knowing that all men are responsible for the crime of the vilest criminal before the judge. I mean if we as the fragments of society (not the victims but the cause) did our part and truly followed the authority of Jesus and His idea of love, selfishness the cause of hunger across the globe would be one of our least trouble. But because our selfishness creates hunger, the criminal before the judge would steal to survive. Thus the idea of Jesus is the idea that not everything is permissible and all men are as responsible for the sin of the worse criminal as the criminal himself.