Precision : I put 5 items in template configuration (seb_blog) 3 top, 1 middle,1 bottom...

Hi

Does the url have something like "start=6" when you click to the next page using the pagination button?

PS I am not helping you as do not know how to, just curious :)

Good question and the answer is yes :

for the second page articles-profession-auxiliaire-veterinaire.html?start=5

for the first one articles-profession-auxiliaire-veterinaire.html?limitstart=0

but always the 10 articles are displayed

Pagination is not set in template configuration, it is set in search type configuration (e.g. list tab + cofiguration tab), there you can select number of shown items. If you show your list in module  this setting will get overriden by the module setting.

It's what I have done... 

Do you display your list in a module? If not try with standard Joomla template, some template frameworks override things they are not supposed to override. Also check if you have accidentally set pagination in menu setting if this is normal list (not module)

Sorry, I forgot : not in a module.

"If not try with standard Joomla template, some template frameworks override things they are not supposed to override. Also check if you have accidentally set pagination in menu setting if this is normal list"