In access, I have a table TIndividus linked to SQL with a column Tind_Sentinelle with Yes, No, NULL.
In my report I need a checkbox based on this column: if the value is Yes the checkbox is checked, else is unchecked.
I have tried to put the name of my column in the data control source but it doesn't work. (I'm new using Access so it's a little bit hard for me.)
Assuming that the field Tind_Sentinelle is a text field containing the literal strings Yes, No (or is null), and also assuming that your table TIndividus is the Record Source for your report, then you should be able to set the Control Source property of your checkbox to the following:
=[tind_sentinelle]="Yes"