Hi Maxime,
Welcome to this Microsoft Project newsgroup
Yes - Tools/Options.../View tab/Date Format - select a format that includes
the time. However, you should be aware that entering Start Dates will
impose a constraint on your project that reduces its flexibility. Project
is not designed for use as a classroom programmer as it expects to calculate
the dates and times for you after you tell it the Duration and the
precedence link.
FAQs, companion products and other useful Project information can be seen at
this web address: <
http://www.mvps.org/project/>
Hope this helps - please let us know how you get on

)
Mike Glen
MS Project MVP