Don't stay at home because of the virus. Most of the places are "sur réservation" : not too many people and safe!
Our tips are :
1 - Do you want to visit some historic mansions in the 7th (usually a "ministère" or an "ambassade")?
Prefer the little ones : l'hôtel de Clermont, 69 rue de Varenne 75007 Paris, an adorable little "hôtel particulier" with historic rooms and garden https://journeesdupatrimoine.culture.gouv.fr/programme#/pinpoints/34765241
2 - Stay in the same area
Rue de Varenne, you can find many mansions with gardens.
L'hôtel de Castries, with its beautiful garden https://journeesdupatrimoine.culture.gouv.fr/programme#/pinpoints/34667299
Le ministère de l'agriculture, with its cute vegetable garden and its impressive meeting room
And... The Musée Rodin (not free), a beautiful urban castle, a beautiful museum with a café in the gardens.
3 - Prefer the large places outdoor
Do you love fashion, art and design?
Go to the Kering and Balenciaga Place, an old renovated hospital (Laennec) with a chapel, art works...
Bon dimanche à Paris! Bonnes visites!