Is madame a proper noun

The noun 'madame' (lower case m) is a common noun, a general Word for an older woman, most commonly used in its contracted form, ma'am.

Example: Please take a seat madam, we'll be with you shortly.

The noun 'Madame' (capital M) is a proper noun as the title of a specific woman.

Example: Madam Chairperson will read the report.