Flower baskets in Paris: 201 French roses, lilies or the florist's pick
Flower baskets in Paris run from 201 French red roses down to Ecuadorian baskets of 51 and 101 stems, red or white. The choice starts with the flower, then moves to the number of stems, and only then to whether you or the florist decides the mix.
French red or Ecuadorian white: the roses a Paris basket is counted in
The 201 French Red Roses basket is the largest rose option here, and "French" names a technique rather than a variety. The florist opens each bloom by hand, turning back the outer petals, which is a finishing touch, not proof the rose grew in France: around eighty per cent of the cut flowers sold in the country are brought in from elsewhere.
The Ecuadorian roses in the same baskets come in smaller counts. 101 White Ecuadorian Roses in a Basket sits alongside matching baskets of 51 and 101 red stems, also grown in Ecuador. The decision here is colour first, red or white, then how many stems the basket should hold.
On 14 February the rose is the flower most given in France, and a Paris basket tends to come in an odd number of stems, 51, 101 or 201, a habit covered in French flower etiquette and dates. Single-variety roses outside these counts are in the roses section.

Lilies by the fifty, or a basket left to the florist's eye
51 Lilies in a Basket is built on a flower grown in greenhouses all year, so this basket can be ordered in any month without waiting for a season to turn.
Lily pollen stains fabric on contact. The orange anthers are usually removed once a bloom has opened, and fresh pollen on a sofa or a sideboard lifts off with sticky tape rather than a rub, which only pushes it in deeper. Lilies are also toxic to cats, worth weighing before sending this basket to a home with one.
For a looser order, choose a florist's designer basket or a basket picked by colour. A designer basket carries the florist's own composition, where the mix of flowers is the florist's call. A colour-picked basket starts from a shade rather than a named flower. Either way, the florist builds the basket to that brief and sends a photo with the price before any payment is taken.
Flower basket delivery in Paris: bought for the order, seen before it leaves
Payment comes before the basket is built: the order is paid first, and the flowers are bought for it afterwards. Inside the basket a liner holds the water in, and a block of wet foam goes in heavy enough to sink on its own, so the stems drink from it without needing a vase.
A photo of the finished basket reaches the sender before the courier sets off, and the order can still be changed up to that point. If a stem isn't available, the florist swaps it for one close in shade and price, and the swap shows in the photo.
The courier hands the basket over in person, along with its card. If the recipient isn't in, and the sender has agreed to it beforehand, the basket goes to a concierge or to neighbours instead.
Most orders are delivered the same day they're placed, and the exact timing for a given basket shows on its own page; zones are listed under delivery. One thing worth checking first: AP-HP wards for intensive care, transplants or very young children turn flowers away at the door.

Where to start depends on what the basket is for. Roses, lilies and the rest sorted by flower sit under baskets built on one flower, a single shade is quickest to find among baskets picked by colour, and leaving the composition to a florist means browsing designer and signature baskets.