Advice Hidden Gems for a Month in Paris

I'm gearing up for a month-long stay in Paris and would love to get some off the beaten path or under-the-radar suggestions. I've been to the city four times already, so I'm looking for experiences that go beyond the usual tourist spots. Any advice on unique neighborhoods, lesser-known museums, or local eateries that really capture the essence of Paris? I'm all ears for anything that could make this trip special!