The values of the European Enlightenment are very specific and I guess it's very difficult to sum them up, but I guess that analyzing the definition of Enlightenment by Kant is a good start.
Kant defines Enlightenment as man's exit from his self-incurring immaturity. I prefer the German term,
Unmuendigkeit, because it expresses this concept perfectly, because it is often used to describe the incapability of interpreting one's will, and to put it into action.
Kant explains that this incapability is due to the lack of courage that religions and political authorities have always inculcated in men. Religions have always tried to explain reality through dogmatic truths, practically depriving men of the courage to defy these truths and look for something alternative.
The values of the so called European Enlightenment so therefore are: - the absolute use of reason to understand and explain reality; the refusal of dogmas; -the total rejection of religious influences in juridic, scientific, economic and social matters; - an anthropocentric vision of the world.
The French Enlightenment was perhaps the most notable for its 'elitist' views though, and the idea that the state should use its power to curb 'regressive' ideologies, and that the educated elite should 'shepherd' the masses, perhaps even forcefully.
He was probably a racialist as well subscribing to theories of the 'lesser races'. This was the precursor of Herbert Spencer's social Darwinism (that predates Darwinian evolution), and to which Darwin himself was at least sympathetic.
Tolerance as an Enlightenment value is a hard sell, and as a French Enlightenment value it is hardest of all.
I didn't mean to imply that in Voltaire's works you cannot find sentences that we, 21st century people, can find very despicable, because they are the result of a culture which still was very ignorant on some subjects like anthropology, genetics, science in general.
Nevertheless, I've read Voltaire in French many times and I know that sometimes his outspokenness and total absence of political correctness (which hardly existed in European culture back then) was often sarcastic.
Besides, Voltaire was the first critic of himself, because he has never believed in absolute truths, or that he was supposed to teach something.
The attitude of these philosophers can be summed up with a phrase of G. E. Lessing: "It is not the truth -that a person possesses or believes to possess- that makes them worthy. It's his sincere effort spent on finding the truth."
By the way, I suppose you are an American, because it is very rare to find an European person who doesn't feel like totally embracing European Enlightenment. That's interesting, because as an European, I know that we have an education system that totally relies on those values, and we are taught to accept them totally and blindly, since they are the foundation of our European identity.
For me Enlightened values are open to individuality, respectful of others values and belief in non-interference of others values.
Ideological tolerance is just one of the many aspects of the philosophic attitude of Enlightenment. But this attitude goes much further than that, because as Voltaire says, it describes that intolerance is almost always caused by religious fanaticism and by the will of establishing absolute truths.
I also deeply believe that Enlightenment is incompatible with a theocentric vision of life.
