Here is a nice comprehensive summary of metro and other closures particularly beginning July 18, when the really intense closures start (keep in mind that Concorde and Tuileries stations are already closed.
The week leading up to the Opening Ceremony (July 18-26) will see a whole host of closures, with closures being most intense on the 26th itself. The staging of the Opening Ceremony along the Seine means that they are restricting access to several places (already, many of the lower quais of the Seine are closed, I’ve seen complaints from joggers whose regular routes are now cut off !).
Keep in mind that while articles like this don’t specify bus closures, bus reroutings are MULTIPLE, given all the closed places they would normally cross (i.e. place de la Concorde, Trocadero, etc.). If your normal means of getting around Paris is by bus in the center, don’t count on that over the next few weeks.
In English, from France24.
Also, an article in Le Parisien this morning notes that RER and suburban train lines will be reduced now from their usual summer slow-downs in order that they can provide more service during the Games. The most-hit line will be the RER C (which ironically is finally completely open this summer instead of closing for months for construction along the central part of the line. that work is now done) - which will only operate at 60% of its normal reduced summer schedule. (Remember, the RER C is the one you use to get out to Versailles.) But again, during the Games, they will be running these lines more frequently in order to get spectators and journalists etc to competition sites. It’s just that before the Games, they will be running fewer (to give more staff a break so they will all come work during the Games).