Bring a large pot of salted water to a boil. Add the green beans and cook until bright green and tender, 4 to 5 minutes. Drain in a colander in the sink and run under cold water, while tossing, in order to stop cooking. Pat dry with paper towels.
Add the bacon to a large heavy skillet set over medium heat and cook until crisp, about 5 minutes. With a slotted spoon, transfer the bacon to a paper-towel-lined plate to drain. Pour off some of the bacon fat from the skillet, if needed, and add the shallot. Saute until tender, about 3 minutes. Toss in the green beans and continue sauteing for 5 minutes. Season with salt and pepper, then add the bacon back to the skillet and stir to combine.