Formal Address
For formal address, Spanish uses the 3rd person singular with Usted when there is only one person and the 3rd person plural when there are several people to address formally. This allows the expression of the French "vous de politesse". The abbreviated form is Ud. or Vd. for usted and Uds. and Vds. for ustedes. The verb that follows is conjugated with the 3rd person endings.
Señor, lo acompaño a Vd. (Sir, I accompany you.)
It should be noted that informal address in Spanish is easier than in France. It is not uncommon for a teacher to naturally address their students informally.