I just ran the script to create your tables and the code failed:

Msg 1767, Level 16, State 0, Line 2

Foreign key 'FK_SOUS_SIT_RENFERMER_SITE' references invalid table 'dbo.SITE'.

Msg 1750, Level 16, State 0, Line 2

Could not create constraint. See previous errors.

Msg 4917, Level 16, State 0, Line 1

Constraint 'FK_SOUS_SIT_RENFERMER_SITE' does not exist.

Msg 4916, Level 16, State 0, Line 1

Could not enable or disable the constraint. See previous errors.

Msg 1767, Level 16, State 0, Line 2

Foreign key 'FK_MOUVEMEN_AVOIR_DESTINAT' references invalid table 'dbo.DESTINATION'.

Msg 1750, Level 16, State 0, Line 2

Could not create constraint. See previous errors.

Msg 4917, Level 16, State 0, Line 2

Constraint 'FK_MOUVEMEN_AVOIR_DESTINAT' does not exist.

Msg 4916, Level 16, State 0, Line 2

Could not enable or disable the constraint. See previous errors.

Msg 1767, Level 16, State 0, Line 2

Foreign key 'FK_MOUVEMEN_EXERCER_EMPLOYER' references invalid table 'dbo.EMPLOYER'.

Msg 1750, Level 16, State 0, Line 2

Could not create constraint. See previous errors.

Msg 4917, Level 16, State 0, Line 2

Constraint 'FK_MOUVEMEN_EXERCER_EMPLOYER' does not exist.

Msg 4916, Level 16, State 0, Line 2

Could not enable or disable the constraint. See previous errors.

Msg 1767, Level 16, State 0, Line 2

Foreign key 'FK_FAIRE_FAIRE_ARTICLE' references invalid table 'dbo.ARTICLE'.

Msg 1750, Level 16, State 0, Line 2

Could not create constraint. See previous errors.

Msg 4917, Level 16, State 0, Line 2

Constraint 'FK_FAIRE_FAIRE_ARTICLE' does not exist.

Msg 4916, Level 16, State 0, Line 2

Could not enable or disable the constraint. See previous errors.

Msg 1767, Level 16, State 0, Line 2

Foreign key 'FK_CONTENIR_CONTENIR_ARTICLE' references invalid table 'dbo.ARTICLE'.

Msg 1750, Level 16, State 0, Line 2

Could not create constraint. See previous errors.

Msg 4917, Level 16, State 0, Line 2

Constraint 'FK_CONTENIR_CONTENIR_ARTICLE' does not exist.

Msg 4916, Level 16, State 0, Line 2

Could not enable or disable the constraint. See previous errors.

Msg 1767, Level 16, State 0, Line 2

Foreign key 'FK_CONTENIR_CONTENIR2_COMMANDE' references invalid table 'dbo.COMMANDE'.

Msg 1750, Level 16, State 0, Line 2

Could not create constraint. See previous errors.

Msg 4917, Level 16, State 0, Line 2

Constraint 'FK_CONTENIR_CONTENIR2_COMMANDE' does not exist.

Msg 4916, Level 16, State 0, Line 2

Could not enable or disable the constraint. See previous errors.

Suggestion, before posting the DDL for your tables run the scripts in an empty database to ensure that they work without errors. I'll check back later to see you have posted new DDL as I don't have time to fix the issues myself.

It does look like it may just be an issue with the order in which things are created.