A suitable gender-neutral email greeting for professional communication is "Hello" or "Greetings."
You can use "Dear" followed by the person's full name in a cover letter as a gender-neutral salutation.
In a professional setting, if you do not know someone's gender, it is appropriate to use gender-neutral terms such as "excuse me," "hello," or "good morning" instead of using the term "sir."
To address a gender-neutral individual in a formal letter using the salutation "Dear," you can simply use their name or a neutral title like "Dear First Name" or "Dear Title Last Name."
The appropriate salutation depends on whether you also are a solicitor in your own country. If you are a female attorney too, then the appropriate salutation is "Chère Consoeur". However most French lawyers use the "Cher Confrère" salutation regardless of the gender of their interlocutor. If you are a man, you can write "Cher Confrère". If you are not an attorney, then the appropriate salutation always is 'Cher Maitre' or simply "Maître".
In a professional setting, the appropriate way to address a nonbinary version of "sir" is to use gender-neutral language such as "Mx." (pronounced "mix") followed by their last name. This shows respect and acknowledges their gender identity.
In a formal setting, the appropriate gender-neutral equivalent of "sir" is to address someone as "Madam" or "Ma'am."
When addressing a formal letter to an unknown recipient, it is appropriate to use the gender-neutral term "Dear Sir or Madam."
When addressing a formal letter to an unknown recipient, it is appropriate to use the gender-neutral term "Dear Sir/Madam."
A situation where a gender-neutral term like "sir madam" would be appropriate is when addressing a group of people in a formal setting, such as a business meeting or a public event, where the gender of the individuals is unknown or irrelevant.
In modern communication, addressing someone as "Dear Sir or Madam" in a formal letter is considered outdated. It is more appropriate to use gender-neutral salutations such as "Dear Title Last Name" or "To Whom It May Concern."
To address a gender-neutral individual in a professional email, you can use "Dear First Name Last Name" or "Dear Job Title" instead of "Dear Sir/Madam."