Suppose, if you find a character é which is not a french, then,
you have to find the correct french character and its ascii value.
After finding the ascii value of the actual french character, you can
update the é using replace command with the correct french character.

1. Find the ascii value of é first.


For ex if I have the é character in the JOB column you can find the ascii value by running the below select statement:

SELECT DUMP(JOB) FROM EMP WHERE EMPNO = 7902;

DUMP(JOB)
--------------------------------------------------------------
Typ=1 Len=7: 65,78,65,76,89,83,84

This will display the ascii value of each character in the job column. You can select the ascii value for é say 83.

2. Now, get the ascii value of the correct one (say 110) which replace the é.

3. Then you can run a update statement like this.

update emp set job=replace(job,chr(83),chr(110)) where empno=7902;

I hope, I am giving you the correct suggestion for your scenario.