So far, I've experienced several significant differences in the cultures of America and France. A very major difference is the responsibility and freedoms given to children and young adults in Grenoble. Because Grenoble is an industrial area and public transportation is prevalent, kids and teenagers travel alone almost everywhere. This is very different from Phoenix, where children are more supervised and it is not as easy to get from one place to another quickly.
Also, greetings in France are different from America. Rather than shake hands, I have been greeting new people with a kiss on each cheek. This is customary for everyone, whether they have met previously or not.
There are also many similarities between the two cultures. For example, I have noticed that many people in Grenoble listen to the same music as me--usually American music or Latin music. Also, the clothing style is very similar to that in America.
The culture in France has some subtle and some signifiant changes from American culture, but it is nothing too drastic and the differences are gradually becoming the norm for me during my stay here.