Replace the glass in your French doors with tempered glass. This type of glass is also known as "safety glass" because it's five times stronger than other types of glass. If your baby falls into it, it won't break.
Place a lever handle lock on the door. Lever handles are fairly simple for toddlers to figure out how to open, so a lock is crucial for more mobile children. The lock is simply pressed in order for adults to open the door.
Keep furniture away from the doors. A toddler climbing on some furniture could easily slip and fall into the door.
Place an extra-large baby gate in the doorway when the doors are open. This will keep your child from wandering outside unsupervised.
Place decals on the glass at your child's eye level. An excited toddler may run around and not notice that a pane of glass is in his way. Placing decals will show your child that he can't run through the door.
Keep any cords out of your child's reach. Nearly 1,000 children die of strangulation every year, and window blind cords account for many of these deaths. If your French doors have any type of shades on them that have a cord, replace them with cordless shades or keep the cords tied in a way that your child can't reach them.