Maria Sharapova, who won the title in Paris in 2012 and lost in the final last year, will need to douse the up-and-coming Bouchard, the 18th seed who has yet to beat a top-ranked player at Roland Garros.
Seventh seed Sharapova has been showing her usual fighting spirit, overcoming the loss of the first set in her last two matches.
The other semi-final on court Philippe Chatrier will feature German 28th seed against Romanian fourth see Simona Halep, who has been blazing her way through the draw.
Halep, who compensates her lack of power with her tactical nous, has lost just over four games per match and has yet to drop a set.
She won the 2008 junior title and will face an opponent she beat a year ago in the final of the Nuremberg claycourt tournament.
Maria Sharapova of Russia returns the ball to Garbine Muguruza of Spain during their women's quarter-final match at the French Open tennis tournament at the Roland Garros stadium in Paris. (Reuters)