The Sagem default Access Code is often 1234. But without you being prepared to say which model it is, it is not possible to be more precise.
The default Access Code for your model will be in the manual. Sagem's manuals are usually easier than some other brands to find and download online.
The previous owner may have changed the Access Code. You can change it back to the default value by locating the default setting. (This will also work on some other makes as well.)
After you have confirmed the valid Access Code you can change it to 0000. With some Sagems having the Access Code to 0000 will disable the Access Code functionality so that it does not ask for it again until after you change it so that it is no longer 0000 anymore.
Updating the firmware will also change the Access Code back to its default, but for the Sagem's I have more knowledge of that is not a feasible solution. Sorry.
Some makes also provide a secret menu accessed by a special sequence of remote button presses. Sagem do not provide this function. Sorry.
NS
July 2012