The notes are as follow:

do (C), ré (D), mi (E), fa (F), sol (G), la (A), si (B).

ut is a synonym for do but it’s not used that much as far as I know.

I’ve never heard of “ti” and I’m pretty much sure it doesn’t exist.

“Sharp” is dièse and is used after the note, so a C sharp would be a do dièse.
Similary, “Flat” is bémol, so a C flat would be… a B… bad example. A E flat is a mi bémol.

See also Note de musique and Désignation des notes de musique suivant la langue on Wikipédia.

So, as Joubarc said the names are do, ré, mi, fa, sol, la and si.

We modulate them with double bémol , bémol ♭, bécarre ♮, dièse ♯ and double dièse .

Ut is nowadays only used in rare expressions like clef d’ut (musical C clef)   or concerto en ut majeur or contre-ut (a high-pitched C in the soprano register).

di or ti are not used at least in France. Maybe in Canada, Switzerland or Belgium it exists, but that is not standard.

Ut is the old name used for do and only found in a few musical expressions such as clef d’ut (C major).

The origin of French/Latin musical notes is quite interesting actually. They are famously taken from the first syllables of a poem in Latin:

Ut queant laxis

Re.sonare fibris

Mi.ra gestorum

Fa.muli tuorum

Sol.ve polluti

La.bii reatum

S.ancte I.ohannes

Ut was eventually replaced for practical reasons (hard to enunciate when reading a partition aloud) by a Giovanni Battista Doni, who used his own name as an inspiration for the new name.

I have never heard of such a thing as di for do dièse…

Ti was once suggested (dixit Wikipedia En) as a replacement for si (in order to have all notes starting with a different letter), but never widely adopted as far as I know.

Both answers by Benoit and Dave are correct.
They are only missing on the ti explanation.

ti is actually used in English when using do, re, mi, fa, sol, la, ti, do… to name (and sing) the degrees of the key, regardless of their real values. It’s called Movable Do.

For instance in D (Ré majeur) the scale would be

• do: D (ré)
• re: E (mi)
• mi: F#(fa dièse)
• fa: G (sol)
• sol: A (la)
• la: B (si)
• ti: C#(do dièse)
• do: D (ré)
• …