I think that one of the most important contributions of Flaubert would be the emphasis on Realism and the construction of reality through art in a manner that was consistent with it. For example, when Flaubert writes Madame Bovary, he spent a great deal of time painfully reconstructing the realistic elements to Emma and her world. It was essential for Flaubert that his representation was true to the realist movement that he was so fond of and with which he was so willing to identify himself. In this, Flaubert was able to raise Realism to a point where the construction of his art and its rendering were both masterful. Flaubert's emphasis on Realism helped to increase the effectiveness of his writing, and in not evading the reality of his protagonists helped to make his contribution to the world stage of literature quite impressive. The fact that Flaubert's work in the Realist movement became such an intense part of his contribution to the world stage of literature was something that made him so important. It is this element that makes Flaubert on the short list of writers that embodied a particular movement and created importance because of it.
Gustave Flaubert (1821-1880) was a French realist novelist. His most famous work is Madame Bovary. The novel tells of Emma Bovary, who is the wife of a doctor. Emma had numerous adulterous affairs and spends more money than is beyond her means in an attempt to escape the realities of her own life. At the time it was published, many people found the topic of an adulterous wife, to be rather controversial.
Today the book is taught in both high schools and colleges, and Emma's activities are often used in classroom discussions as to whether or not we are more accepting of women having audlterous affairs today.