Nice size poster. Very close to a classic French 1P size (47x63 inches).
Because Beauvais moved back to France (Marseille) in 1902-1903, after a 20 year stint in London, and setting up his own studio, there certainly is a good chance that your circus poster was produced sometime in the years he moved back and his death in 1909 (another source said he passed on in 1911).
Fingers crossed that your poster has some identifying printer's info on the border, too.
Even this little blurb from his great granddaughter was interesting:
Dear Mr Hendricks
I have been researching my family tree recently on the Beauvais side of our family. My Great Grandfather was Charles Henri Beauvais, a lithographer and artist. I was surfing on the net trying to find examples his commercial work, and up popped your Tonik Polo poster (I also found a couple of his other works - One called 'La Micheline' which has been reproduced as a poster).
I thought that you might appreciate a bit of information about the artist:
Charles Henri Beauvais was born in Marseille in 1862. He came to live and work in London in about 1881 as a lithographer. It was in London that he met my Great Grandmother Emily Anne. They had six children. Around about 1902 - 3 he moved himself and all his family back to France, back to his hometown, Marseille where he set up a studio. Sadly, he died in 1909. His widow returned to London. Several of his children and grandchildren inherited his artistic talents.
Feel free to contact me if you need any other information.
Regards,
Annette