May Day Protests!
May 1st is traditionally a day to march and protest (this year the theme will be the perceived xenophobia of the French government) and as this year it falls on a Sunday, it is possible that many more people than normal may be taking to the streets. The march begins at 2.30pm at the Place de la République.
For those looking for places to avoid on Sunday, note also that a smaller annual Front National march takes place in the morning in the Opéra/Madeleine area.
On a brighter note, the streets should also be alive with the sweet smell of 'muguet' (lily of the valley) flowers which are traditionally sold everywhere on May 1st.
As Sunday May 1st is also a Bank Holiday, the question of whether certain sites are open or closed becomes complicated. The answers to your questions can be found here: http://www.paris.fr/accueil/accueil-paris-fr/paques-ouvert-ferme/rub_1_actu_83411_port_24329
Note that most museums and almost all swimming pools will be closed.
Foire de Paris
The Foire de Paris is 107 years old this year, and is a meandering bazaar incorporating 3400 exhibitors spread over 220,000m². Fortunately, as the theme this year is 'slow time', the experience should nevertheless not be too stressful!
The event was originally held at the Carreau de Temple, before becoming the reason behind the creation of its present home, the Parc des Expositions at the Porte de Versailles. Alongside the home, food and leisure exhibits, an interesting curiousity is the Concours Lépine which makes up part of the event. This annual competition rewards the best inventions of the year, and previous winners have included ballpoint pens, the iron and contact lenses!
Full details can be found here: http://www.foiredeparis.fr/
The Impressionists in Paris
Already a big draw, this exhibition at the Paris town hall (Hotel de Ville) shows how impressionist painters, incluidng Monet, Vuillard and Degas, captured Paris.
More details, including location and opening times can be found here: http://www.paris.fr/english/english/event-the-impressionists-at-the-hotel-de-ville-in-paris/rub_8118_actu_97309_port_19237
Note: this exhibition is one of those that will not be open on Sunday.
Art et Folie
The Hôpital Saint Anne in Paris is home to an unusual collection of 'psychopathological art', and even organised annual exhibitions of creations from around the world from people suffering from mental illnesses. To celebrate the 60th anniversary of one of these exhibitions, the Area gallery is exhibiting a selection of some of these creations.
Full details can be found here: http://www.areaparis.com/